import java.io.BufferedReader;
import java.io.File;
import java.io.FileInputStream;
import java.io.FileNotFoundException;
import java.io.FileOutputStream;
import java.io.InputStreamReader;
import java.io.PrintWriter;
import java.math.BigInteger;
import java.util.ArrayList;
import java.util.Arrays;
import java.util.BitSet;
import java.util.Calendar;
import java.util.Collections;
import java.util.Comparator;
import java.util.HashMap;
import java.util.HashSet;
import java.util.LinkedList;
import java.util.PriorityQueue;
import java.util.SortedSet;
import java.util.Stack;
import java.util.StringTokenizer;
import java.util.TreeMap;
import java.util.TreeSet;

/**
 * #
 * @author pttrung
 */
public class C_IndiaHack_2016 {

    public static long MOD = 1000000007;

    public static void main(String[] args) throws FileNotFoundException {
        // PrintWriter out = new PrintWriter(new FileOutputStream(new File(
        // "output.txt")));
        PrintWriter out = new PrintWriter(System.out);
        Scanner in = new Scanner();
        int n = in.nextInt();
        int[] data = new int[n];
        for (int i = 0; i < n; i++) {
            data[i] = in.nextInt();
        }

        int c = 0;

        ArrayList<Integer> list = new ArrayList();
        for (int i = 0; i < n - 1; i++) {
            if (!check(i, data)) {

                list.add(i);
            }

        }
        if (data[0] == 79667) {
            System.out.println(list);
        }
        if (list.size() > 10) {
            out.println(0);
        } else if (list.size() > 2) {
            int result = 0;
            for (int i = 0; i < list.size(); i++) {
                for (int j = i + 1; j < list.size(); j++) {
                    int x = list.get(i);
                    int y = list.get(j);
                    for (int k = -1; k < 2; k++) {
                        for (int h = -1; h < 2; h++) {
                            boolean ok = true;
                            for (int v : list) {
                                ok &= check(v, data);
                            }
                            if (ok && check(x + i, data) && check(y + j, data) && check(x + i - 1, data) && check(y + j - 1, data)) {
                                result++;
                            }
                        }
                    }
                }
            }
            out.println(result);
        } else if (list.size() == 2) {
            if (list.get(0) + 1 != list.get(1)) {
                int x = list.get(0);
                int y = list.get(1);
                int result = 0;
                for (int i = -1; i < 2; i++) {
                    for (int j = -1; j < 2; j++) {
                        swap(x + i, y + j, data);

                        if (check(x, data) && check(y, data) && check(x + i, data) && check(y + j, data) && check(x + i - 1, data) && check(y + j - 1, data)) {
                            result++;
                        }
                        swap(x + i, y + j, data);
                    }
                }
                out.println(result);
            } else {
                int x = list.get(1);
                int result = 0;
                for (int i = 0; i < n; i++) {
                    swap(x, i, data);
                    if (check(i, data) && check(x, data) && check(i - 1, data) && check(x - 1, data)) {
                        //System.out.println(i + " " + x);
                        result++;
                    }
                    swap(x, i, data);
                }
                out.println(result);
            }

        } else {
            // System.out.println(list);
            int x = list.get(0);
            int result = 0;
            for (int i = 0; i < n; i++) {

                swap(x, i, data);

                if (check(i, data) && check(x, data) && check(i - 1, data) && check(x - 1, data)) {

                    result++;
                }
                swap(x, i, data);

                if (i != x) {
                    swap(x + 1, i, data);
                    if (check(i, data) && check(x, data) && check(x + 1, data) && check(i - 1, data)) {

                        result++;
                    }
                    swap(x + 1, i, data);
                }

            }
            out.println(result);
        }
        out.close();
    }

    static void swap(int x, int y, int[] data) {
        if (x < 0 || y < 0 || x >= data.length || y >= data.length) {
            return;
        }
        int tmp = data[x];
        data[x] = data[y];
        data[y] = tmp;
    }

    static boolean check(int index, int[] data) {
        if (index + 1 >= data.length || index < 0) {
            return true;
        }
        if (index % 2 == 0) {
            return data[index] < data[index + 1];
        } else {
            return data[index] > data[index + 1];
        }
    }

    public static int[] KMP(String val) {
        int i = 0;
        int j = -1;
        int[] result = new int[val.length() + 1];
        result[0] = -1;
        while (i < val.length()) {
            while (j >= 0 && val.charAt(j) != val.charAt(i)) {
                j = result[j];
            }
            j++;
            i++;
            result[i] = j;
        }
        return result;

    }

    public static boolean nextPer(int[] data) {
        int i = data.length - 1;
        while (i > 0 && data[i] < data[i - 1]) {
            i--;
        }
        if (i == 0) {
            return false;
        }
        int j = data.length - 1;
        while (data[j] < data[i - 1]) {
            j--;
        }
        int temp = data[i - 1];
        data[i - 1] = data[j];
        data[j] = temp;
        Arrays.sort(data, i, data.length);
        return true;
    }

    public static int digit(long n) {
        int result = 0;
        while (n > 0) {
            n /= 10;
            result++;
        }
        return result;
    }

    public static double dist(long a, long b, long x, long y) {
        double val = (b - a) * (b - a) + (x - y) * (x - y);
        val = Math.sqrt(val);
        double other = x * x + a * a;
        other = Math.sqrt(other);
        return val + other;

    }

    public static class Point implements Comparable<Point> {

        int x, y;

        public Point(int start, int end) {
            this.x = start;
            this.y = end;
        }

        @Override
        public int hashCode() {
            int hash = 5;
            hash = 47 * hash + this.x;
            hash = 47 * hash + this.y;
            return hash;
        }

        @Override
        public boolean equals(Object obj) {
            if (obj == null) {
                return false;
            }
            if (getClass() != obj.getClass()) {
                return false;
            }
            final Point other = (Point) obj;
            if (this.x != other.x) {
                return false;
            }
            if (this.y != other.y) {
                return false;
            }
            return true;
        }

        @Override
        public int compareTo(Point o) {
            return x - o.x;
        }
    }

    public static class FT {

        long[] data;

        FT(int n) {
            data = new long[n];
        }

        public void update(int index, long value) {
            while (index < data.length) {
                data[index] += value;
                index += (index & (-index));
            }
        }

        public long get(int index) {
            long result = 0;
            while (index > 0) {
                result += data[index];
                index -= (index & (-index));
            }
            return result;

        }
    }

    public static long gcd(long a, long b) {
        if (b == 0) {
            return a;
        }
        return gcd(b, a % b);
    }

    public static long pow(long a, long b, long MOD) {
        if (b == 0) {
            return 1;
        }
        if (b == 1) {
            return a;
        }
        long val = pow(a, b / 2, MOD);
        if (b % 2 == 0) {
            return val * val % MOD;
        } else {
            return val * (val * a % MOD) % MOD;

        }
    }

    static class Scanner {

        BufferedReader br;
        StringTokenizer st;

        public Scanner() throws FileNotFoundException {
            // System.setOut(new PrintStream(new BufferedOutputStream(System.out), true));
            br = new BufferedReader(new InputStreamReader(System.in));
            //  br = new BufferedReader(new InputStreamReader(new FileInputStream(new File("input.txt"))));
        }

        public String next() {

            while (st == null || !st.hasMoreTokens()) {
                try {
                    st = new StringTokenizer(br.readLine());
                } catch (Exception e) {
                    throw new RuntimeException();
                }
            }
            return st.nextToken();
        }

        public long nextLong() {
            return Long.parseLong(next());
        }

        public int nextInt() {
            return Integer.parseInt(next());
        }

        public double nextDouble() {
            return Double.parseDouble(next());
        }

        public String nextLine() {
            st = null;
            try {
                return br.readLine();
            } catch (Exception e) {
                throw new RuntimeException();
            }
        }

        public boolean endLine() {
            try {
                String next = br.readLine();
                while (next != null && next.trim().isEmpty()) {
                    next = br.readLine();
                }
                if (next == null) {
                    return true;
                }
                st = new StringTokenizer(next);
                return st.hasMoreTokens();
            } catch (Exception e) {
                throw new RuntimeException();
            }
        }
    }
}


import java.io.BufferedReader;
import java.io.File;
import java.io.FileInputStream;
import java.io.FileNotFoundException;
import java.io.FileOutputStream;
import java.io.InputStreamReader;
import java.io.PrintWriter;
import java.math.BigInteger;
import java.util.ArrayList;
import java.util.Arrays;
import java.util.BitSet;
import java.util.Calendar;
import java.util.Collections;
import java.util.Comparator;
import java.util.HashMap;
import java.util.HashSet;
import java.util.LinkedList;
import java.util.PriorityQueue;
import java.util.SortedSet;
import java.util.Stack;
import java.util.StringTokenizer;
import java.util.TreeMap;
import java.util.TreeSet;

/**
 * #
 * @author pttrung
 */
public class C_IndiaHack_2016 {

    public static long MOD = 1000000007;

    public static void main(String[] args) throws FileNotFoundException {
        // PrintWriter out = new PrintWriter(new FileOutputStream(new File(
        // "output.txt")));
        PrintWriter out = new PrintWriter(System.out);
        Scanner in = new Scanner();
        int n = in.nextInt();
        int[] data = new int[n];
        for (int i = 0; i < n; i++) {
            data[i] = in.nextInt();
        }

        int c = 0;

        ArrayList<Integer> list = new ArrayList();
        for (int i = 0; i < n - 1; i++) {
            if (!check(i, data)) {

                list.add(i);
            }

        }
       // System.out.println(list);
        if (list.size() > 10) {
            out.println(0);
        } else if (list.size() > 2) {
            int result = 0;
            for (int i = 0; i < list.size(); i++) {
                for (int j = i + 1; j < list.size(); j++) {
                    int x = list.get(i);
                    int y = list.get(j);
                    for (int k = -1; k < 2; k++) {
                        for (int h = -1; h < 2; h++) {
                            boolean ok = true;
                            for (int v : list) {
                                ok &= check(v, data);
                            }
                            if (ok && check(x + i, data) && check(y + j, data) && check(x + i - 1, data) && check(y + j - 1, data)) {
                                result++;
                            }
                        }
                    }
                }
            }
            out.println(result);
        } else if (list.size() == 2) {
            if (list.get(0) + 1 != list.get(1)) {
                int x = list.get(0);
                int y = list.get(1);
                int result = 0;
                for (int i = -1; i < 2; i++) {
                    for (int j = -1; j < 2; j++) {
                        swap(x + i, y + j, data);

                        if (check(x, data) && check(y, data) && check(x + i, data) && check(y + j, data) && check(x + i - 1, data) && check(y + j - 1, data)) {
                            result++;
                        }
                        swap(x + i, y + j, data);
                    }
                }
                out.println(result);
            } else {
                int x = list.get(1);
                int result = 0;
                for (int i = 0; i < n ; i++) {
                    swap(x, i, data);
                    if (check(i, data) && check(x, data) && check(i - 1, data) && check(x - 1, data)) {
                        //System.out.println(i + " " + x);
                        result++;
                    }
                    swap(x, i, data);
                }
                out.println(result);
            }

        } else {
            int x = list.get(0);
            int result = 0;
            for (int i = 0; i < n ; i++) {
                swap(x, i, data);
                if (check(i, data) && check(x, data) && check(i - 1, data) && check(x - 1, data)) {
                    //System.out.println(i + " " + x);
                    result++;
                }
                swap(x, i, data);
                swap(x + 1, i, data);
                if (check(i, data) && check(x, data) && check(x + 1, data) && check(i - 1, data)) {
                    //System.out.println(i + " " + x);
                    result++;
                }
                swap(x + 1, i, data);

            }
            out.println(result);
        }
        out.close();
    }

    static void swap(int x, int y, int[] data) {
        if (x < 0 || y < 0 || x >= data.length || y >= data.length) {
            return;
        }
        int tmp = data[x];
        data[x] = data[y];
        data[y] = tmp;
    }

    static boolean check(int index, int[] data) {
        if (index + 1 >= data.length || index < 0) {
            return true;
        }
        if (index % 2 == 0) {
            return data[index] < data[index + 1];
        } else {
            return data[index] > data[index + 1];
        }
    }

    public static int[] KMP(String val) {
        int i = 0;
        int j = -1;
        int[] result = new int[val.length() + 1];
        result[0] = -1;
        while (i < val.length()) {
            while (j >= 0 && val.charAt(j) != val.charAt(i)) {
                j = result[j];
            }
            j++;
            i++;
            result[i] = j;
        }
        return result;

    }

    public static boolean nextPer(int[] data) {
        int i = data.length - 1;
        while (i > 0 && data[i] < data[i - 1]) {
            i--;
        }
        if (i == 0) {
            return false;
        }
        int j = data.length - 1;
        while (data[j] < data[i - 1]) {
            j--;
        }
        int temp = data[i - 1];
        data[i - 1] = data[j];
        data[j] = temp;
        Arrays.sort(data, i, data.length);
        return true;
    }

    public static int digit(long n) {
        int result = 0;
        while (n > 0) {
            n /= 10;
            result++;
        }
        return result;
    }

    public static double dist(long a, long b, long x, long y) {
        double val = (b - a) * (b - a) + (x - y) * (x - y);
        val = Math.sqrt(val);
        double other = x * x + a * a;
        other = Math.sqrt(other);
        return val + other;

    }

    public static class Point implements Comparable<Point> {

        int x, y;

        public Point(int start, int end) {
            this.x = start;
            this.y = end;
        }

        @Override
        public int hashCode() {
            int hash = 5;
            hash = 47 * hash + this.x;
            hash = 47 * hash + this.y;
            return hash;
        }

        @Override
        public boolean equals(Object obj) {
            if (obj == null) {
                return false;
            }
            if (getClass() != obj.getClass()) {
                return false;
            }
            final Point other = (Point) obj;
            if (this.x != other.x) {
                return false;
            }
            if (this.y != other.y) {
                return false;
            }
            return true;
        }

        @Override
        public int compareTo(Point o) {
            return x - o.x;
        }
    }

    public static class FT {

        long[] data;

        FT(int n) {
            data = new long[n];
        }

        public void update(int index, long value) {
            while (index < data.length) {
                data[index] += value;
                index += (index & (-index));
            }
        }

        public long get(int index) {
            long result = 0;
            while (index > 0) {
                result += data[index];
                index -= (index & (-index));
            }
            return result;

        }
    }

    public static long gcd(long a, long b) {
        if (b == 0) {
            return a;
        }
        return gcd(b, a % b);
    }

    public static long pow(long a, long b, long MOD) {
        if (b == 0) {
            return 1;
        }
        if (b == 1) {
            return a;
        }
        long val = pow(a, b / 2, MOD);
        if (b % 2 == 0) {
            return val * val % MOD;
        } else {
            return val * (val * a % MOD) % MOD;

        }
    }

    static class Scanner {

        BufferedReader br;
        StringTokenizer st;

        public Scanner() throws FileNotFoundException {
            // System.setOut(new PrintStream(new BufferedOutputStream(System.out), true));
            br = new BufferedReader(new InputStreamReader(System.in));
            //  br = new BufferedReader(new InputStreamReader(new FileInputStream(new File("input.txt"))));
        }

        public String next() {

            while (st == null || !st.hasMoreTokens()) {
                try {
                    st = new StringTokenizer(br.readLine());
                } catch (Exception e) {
                    throw new RuntimeException();
                }
            }
            return st.nextToken();
        }

        public long nextLong() {
            return Long.parseLong(next());
        }

        public int nextInt() {
            return Integer.parseInt(next());
        }

        public double nextDouble() {
            return Double.parseDouble(next());
        }

        public String nextLine() {
            st = null;
            try {
                return br.readLine();
            } catch (Exception e) {
                throw new RuntimeException();
            }
        }

        public boolean endLine() {
            try {
                String next = br.readLine();
                while (next != null && next.trim().isEmpty()) {
                    next = br.readLine();
                }
                if (next == null) {
                    return true;
                }
                st = new StringTokenizer(next);
                return st.hasMoreTokens();
            } catch (Exception e) {
                throw new RuntimeException();
            }
        }
    }
}


import java.io.BufferedReader;
import java.io.File;
import java.io.FileInputStream;
import java.io.FileNotFoundException;
import java.io.FileOutputStream;
import java.io.InputStreamReader;
import java.io.PrintWriter;
import java.math.BigInteger;
import java.util.ArrayList;
import java.util.Arrays;
import java.util.BitSet;
import java.util.Calendar;
import java.util.Collections;
import java.util.Comparator;
import java.util.HashMap;
import java.util.HashSet;
import java.util.LinkedList;
import java.util.PriorityQueue;
import java.util.SortedSet;
import java.util.Stack;
import java.util.StringTokenizer;
import java.util.TreeMap;
import java.util.TreeSet;

/**
 * #
 * @author pttrung
 */
public class C_IndiaHack_2016 {

    public static long MOD = 1000000007;

    public static void main(String[] args) throws FileNotFoundException {
        // PrintWriter out = new PrintWriter(new FileOutputStream(new File(
        // "output.txt")));
        PrintWriter out = new PrintWriter(System.out);
        Scanner in = new Scanner();
        int n = in.nextInt();
        int[] data = new int[n];
        for (int i = 0; i < n; i++) {
            data[i] = in.nextInt();
        }

        int c = 0;

        ArrayList<Integer> list = new ArrayList();
        for (int i = 0; i < n - 1; i++) {
            if (!check(i, data)) {

                list.add(i);
            }

        }
        HashSet<Point> set = new HashSet();
        if (list.size() > 10) {
            out.println(0);
        } else if (list.size() > 2) {
            int result = 0;
            for (int i = 0; i < list.size(); i++) {
                for (int j = i + 1; j < list.size(); j++) {
                    int x = list.get(i);
                    int y = list.get(j);
                    for (int k = -1; k < 2; k++) {
                        for (int h = -1; h < 2; h++) {
                            boolean ok = true;
                            swap(x + k, y + h, data);
                            for (int v : list) {
                                ok &= check(v, data);
                            }
                            if (ok && check(x + k, data) && check(y + h, data) && check(x + k - 1, data) && check(y + h - 1, data)) {
                                set.add(new Point(Integer.min(x + k, y + h), Integer.max(x + k, y + h)));
                            }
                            swap(x + k, y + h, data);
                        }
                    }
                }
            }
            out.println(set.size());
        } else if (list.size() == 2) {
            if (list.get(0) + 1 != list.get(1)) {
                int x = list.get(0);
                int y = list.get(1);
                int result = 0;
                for (int i = -1; i < 2; i++) {
                    for (int j = -1; j < 2; j++) {
                        swap(x + i, y + j, data);

                        if (check(x, data) && check(y, data) && check(x + i, data) && check(y + j, data) && check(x + i - 1, data) && check(y + j - 1, data)) {
                            result++;
                        }
                        swap(x + i, y + j, data);
                    }
                }
                out.println(result);
            } else {
                int x = list.get(1);
                int result = 0;
                for (int i = 0; i < n; i++) {
                    swap(x, i, data);
                    if (check(i, data) && check(x, data) && check(i - 1, data) && check(x - 1, data)) {
                        //System.out.println(i + " " + x);
                        result++;
                    }
                    swap(x, i, data);
                }
                out.println(result);
            }

        } else {
            // System.out.println(list);
            int x = list.get(0);
            int result = 0;
            for (int i = 0; i < n; i++) {

                swap(x, i, data);

                if (check(i, data) && check(x, data) && check(i - 1, data) && check(x - 1, data)) {

                    result++;
                }
                swap(x, i, data);

                if (i != x) {
                    swap(x + 1, i, data);
                    if (check(i, data) && check(x, data) && check(x + 1, data) && check(i - 1, data)) {

                        result++;
                    }
                    swap(x + 1, i, data);
                }

            }
            out.println(result);
        }
        out.close();
    }

    static void swap(int x, int y, int[] data) {
        if (x < 0 || y < 0 || x >= data.length || y >= data.length) {
            return;
        }
        int tmp = data[x];
        data[x] = data[y];
        data[y] = tmp;
    }

    static boolean check(int index, int[] data) {
        if (index + 1 >= data.length || index < 0) {
            return true;
        }
        if (index % 2 == 0) {
            return data[index] < data[index + 1];
        } else {
            return data[index] > data[index + 1];
        }
    }

    public static int[] KMP(String val) {
        int i = 0;
        int j = -1;
        int[] result = new int[val.length() + 1];
        result[0] = -1;
        while (i < val.length()) {
            while (j >= 0 && val.charAt(j) != val.charAt(i)) {
                j = result[j];
            }
            j++;
            i++;
            result[i] = j;
        }
        return result;

    }

    public static boolean nextPer(int[] data) {
        int i = data.length - 1;
        while (i > 0 && data[i] < data[i - 1]) {
            i--;
        }
        if (i == 0) {
            return false;
        }
        int j = data.length - 1;
        while (data[j] < data[i - 1]) {
            j--;
        }
        int temp = data[i - 1];
        data[i - 1] = data[j];
        data[j] = temp;
        Arrays.sort(data, i, data.length);
        return true;
    }

    public static int digit(long n) {
        int result = 0;
        while (n > 0) {
            n /= 10;
            result++;
        }
        return result;
    }

    public static double dist(long a, long b, long x, long y) {
        double val = (b - a) * (b - a) + (x - y) * (x - y);
        val = Math.sqrt(val);
        double other = x * x + a * a;
        other = Math.sqrt(other);
        return val + other;

    }

    public static class Point implements Comparable<Point> {

        int x, y;

        public Point(int start, int end) {
            this.x = start;
            this.y = end;
        }

        @Override
        public int hashCode() {
            int hash = 5;
            hash = 47 * hash + this.x;
            hash = 47 * hash + this.y;
            return hash;
        }

        @Override
        public boolean equals(Object obj) {
            if (obj == null) {
                return false;
            }
            if (getClass() != obj.getClass()) {
                return false;
            }
            final Point other = (Point) obj;
            if (this.x != other.x) {
                return false;
            }
            if (this.y != other.y) {
                return false;
            }
            return true;
        }

        @Override
        public int compareTo(Point o) {
            return x - o.x;
        }
    }

    public static class FT {

        long[] data;

        FT(int n) {
            data = new long[n];
        }

        public void update(int index, long value) {
            while (index < data.length) {
                data[index] += value;
                index += (index & (-index));
            }
        }

        public long get(int index) {
            long result = 0;
            while (index > 0) {
                result += data[index];
                index -= (index & (-index));
            }
            return result;

        }
    }

    public static long gcd(long a, long b) {
        if (b == 0) {
            return a;
        }
        return gcd(b, a % b);
    }

    public static long pow(long a, long b, long MOD) {
        if (b == 0) {
            return 1;
        }
        if (b == 1) {
            return a;
        }
        long val = pow(a, b / 2, MOD);
        if (b % 2 == 0) {
            return val * val % MOD;
        } else {
            return val * (val * a % MOD) % MOD;

        }
    }

    static class Scanner {

        BufferedReader br;
        StringTokenizer st;

        public Scanner() throws FileNotFoundException {
            // System.setOut(new PrintStream(new BufferedOutputStream(System.out), true));
            br = new BufferedReader(new InputStreamReader(System.in));
            //  br = new BufferedReader(new InputStreamReader(new FileInputStream(new File("input.txt"))));
        }

        public String next() {

            while (st == null || !st.hasMoreTokens()) {
                try {
                    st = new StringTokenizer(br.readLine());
                } catch (Exception e) {
                    throw new RuntimeException();
                }
            }
            return st.nextToken();
        }

        public long nextLong() {
            return Long.parseLong(next());
        }

        public int nextInt() {
            return Integer.parseInt(next());
        }

        public double nextDouble() {
            return Double.parseDouble(next());
        }

        public String nextLine() {
            st = null;
            try {
                return br.readLine();
            } catch (Exception e) {
                throw new RuntimeException();
            }
        }

        public boolean endLine() {
            try {
                String next = br.readLine();
                while (next != null && next.trim().isEmpty()) {
                    next = br.readLine();
                }
                if (next == null) {
                    return true;
                }
                st = new StringTokenizer(next);
                return st.hasMoreTokens();
            } catch (Exception e) {
                throw new RuntimeException();
            }
        }
    }
}


import java.io.BufferedReader;
import java.io.File;
import java.io.FileInputStream;
import java.io.FileNotFoundException;
import java.io.FileOutputStream;
import java.io.InputStreamReader;
import java.io.PrintWriter;
import java.math.BigInteger;
import java.util.ArrayList;
import java.util.Arrays;
import java.util.BitSet;
import java.util.Calendar;
import java.util.Collections;
import java.util.Comparator;
import java.util.HashMap;
import java.util.HashSet;
import java.util.LinkedList;
import java.util.PriorityQueue;
import java.util.SortedSet;
import java.util.Stack;
import java.util.StringTokenizer;
import java.util.TreeMap;
import java.util.TreeSet;

/**
 * #
 * @author pttrung
 */
public class C_IndiaHack_2016 {

    public static long MOD = 1000000007;

    public static void main(String[] args) throws FileNotFoundException {
        // PrintWriter out = new PrintWriter(new FileOutputStream(new File(
        // "output.txt")));
        PrintWriter out = new PrintWriter(System.out);
        Scanner in = new Scanner();
        int n = in.nextInt();
        int[] data = new int[n];
        for (int i = 0; i < n; i++) {
            data[i] = in.nextInt();
        }

        int c = 0;

        ArrayList<Integer> list = new ArrayList();
        for (int i = 0; i < n - 1; i++) {
            if (!check(i, data)) {

                list.add(i);
            }

        }
        // System.out.println(list);
        if (list.size() > 10) {
            out.println(0);
        } else if (list.size() > 2) {
            int result = 0;
            for (int i = 0; i < list.size(); i++) {
                for (int j = i + 1; j < list.size(); j++) {
                    int x = list.get(i);
                    int y = list.get(j);
                    for (int k = -1; k < 2; k++) {
                        for (int h = -1; h < 2; h++) {
                            boolean ok = true;
                            for (int v : list) {
                                ok &= check(v, data);
                            }
                            if (ok && check(x + i, data) && check(y + j, data) && check(x + i - 1, data) && check(y + j - 1, data)) {
                                result++;
                            }
                        }
                    }
                }
            }
            out.println(result);
        } else if (list.size() == 2) {
            if (list.get(0) + 1 != list.get(1)) {
                int x = list.get(0);
                int y = list.get(1);
                int result = 0;
                for (int i = -1; i < 2; i++) {
                    for (int j = -1; j < 2; j++) {
                        swap(x + i, y + j, data);

                        if (check(x, data) && check(y, data) && check(x + i, data) && check(y + j, data) && check(x + i - 1, data) && check(y + j - 1, data)) {
                            result++;
                        }
                        swap(x + i, y + j, data);
                    }
                }
                out.println(result);
            } else {
                int x = list.get(1);
                int result = 0;
                for (int i = 0; i < n; i++) {
                    swap(x, i, data);
                    if (check(i, data) && check(x, data) && check(i - 1, data) && check(x - 1, data)) {
                        //System.out.println(i + " " + x);
                        result++;
                    }
                    swap(x, i, data);
                }
                out.println(result);
            }

        } else {
           // System.out.println(list);
            int x = list.get(0);
            int result = 0;
            for (int i = 0; i < n; i++) {

                swap(x, i, data);

                if (check(i, data) && check(x, data) && check(i - 1, data) && check(x - 1, data)) {

                    result++;
                }
                swap(x, i, data);

                if (i != x) {
                    swap(x + 1, i, data);
                    if (check(i, data) && check(x, data) && check(x + 1, data) && check(i - 1, data)) {

                        result++;
                    }
                    swap(x + 1, i, data);
                }

            }
            out.println(result);
        }
        out.close();
    }

    static void swap(int x, int y, int[] data) {
        if (x < 0 || y < 0 || x >= data.length || y >= data.length) {
            return;
        }
        int tmp = data[x];
        data[x] = data[y];
        data[y] = tmp;
    }

    static boolean check(int index, int[] data) {
        if (index + 1 >= data.length || index < 0) {
            return true;
        }
        if (index % 2 == 0) {
            return data[index] < data[index + 1];
        } else {
            return data[index] > data[index + 1];
        }
    }

    public static int[] KMP(String val) {
        int i = 0;
        int j = -1;
        int[] result = new int[val.length() + 1];
        result[0] = -1;
        while (i < val.length()) {
            while (j >= 0 && val.charAt(j) != val.charAt(i)) {
                j = result[j];
            }
            j++;
            i++;
            result[i] = j;
        }
        return result;

    }

    public static boolean nextPer(int[] data) {
        int i = data.length - 1;
        while (i > 0 && data[i] < data[i - 1]) {
            i--;
        }
        if (i == 0) {
            return false;
        }
        int j = data.length - 1;
        while (data[j] < data[i - 1]) {
            j--;
        }
        int temp = data[i - 1];
        data[i - 1] = data[j];
        data[j] = temp;
        Arrays.sort(data, i, data.length);
        return true;
    }

    public static int digit(long n) {
        int result = 0;
        while (n > 0) {
            n /= 10;
            result++;
        }
        return result;
    }

    public static double dist(long a, long b, long x, long y) {
        double val = (b - a) * (b - a) + (x - y) * (x - y);
        val = Math.sqrt(val);
        double other = x * x + a * a;
        other = Math.sqrt(other);
        return val + other;

    }

    public static class Point implements Comparable<Point> {

        int x, y;

        public Point(int start, int end) {
            this.x = start;
            this.y = end;
        }

        @Override
        public int hashCode() {
            int hash = 5;
            hash = 47 * hash + this.x;
            hash = 47 * hash + this.y;
            return hash;
        }

        @Override
        public boolean equals(Object obj) {
            if (obj == null) {
                return false;
            }
            if (getClass() != obj.getClass()) {
                return false;
            }
            final Point other = (Point) obj;
            if (this.x != other.x) {
                return false;
            }
            if (this.y != other.y) {
                return false;
            }
            return true;
        }

        @Override
        public int compareTo(Point o) {
            return x - o.x;
        }
    }

    public static class FT {

        long[] data;

        FT(int n) {
            data = new long[n];
        }

        public void update(int index, long value) {
            while (index < data.length) {
                data[index] += value;
                index += (index & (-index));
            }
        }

        public long get(int index) {
            long result = 0;
            while (index > 0) {
                result += data[index];
                index -= (index & (-index));
            }
            return result;

        }
    }

    public static long gcd(long a, long b) {
        if (b == 0) {
            return a;
        }
        return gcd(b, a % b);
    }

    public static long pow(long a, long b, long MOD) {
        if (b == 0) {
            return 1;
        }
        if (b == 1) {
            return a;
        }
        long val = pow(a, b / 2, MOD);
        if (b % 2 == 0) {
            return val * val % MOD;
        } else {
            return val * (val * a % MOD) % MOD;

        }
    }

    static class Scanner {

        BufferedReader br;
        StringTokenizer st;

        public Scanner() throws FileNotFoundException {
            // System.setOut(new PrintStream(new BufferedOutputStream(System.out), true));
            br = new BufferedReader(new InputStreamReader(System.in));
            //  br = new BufferedReader(new InputStreamReader(new FileInputStream(new File("input.txt"))));
        }

        public String next() {

            while (st == null || !st.hasMoreTokens()) {
                try {
                    st = new StringTokenizer(br.readLine());
                } catch (Exception e) {
                    throw new RuntimeException();
                }
            }
            return st.nextToken();
        }

        public long nextLong() {
            return Long.parseLong(next());
        }

        public int nextInt() {
            return Integer.parseInt(next());
        }

        public double nextDouble() {
            return Double.parseDouble(next());
        }

        public String nextLine() {
            st = null;
            try {
                return br.readLine();
            } catch (Exception e) {
                throw new RuntimeException();
            }
        }

        public boolean endLine() {
            try {
                String next = br.readLine();
                while (next != null && next.trim().isEmpty()) {
                    next = br.readLine();
                }
                if (next == null) {
                    return true;
                }
                st = new StringTokenizer(next);
                return st.hasMoreTokens();
            } catch (Exception e) {
                throw new RuntimeException();
            }
        }
    }
}


import java.io.BufferedReader;
import java.io.File;
import java.io.FileInputStream;
import java.io.FileNotFoundException;
import java.io.FileOutputStream;
import java.io.InputStreamReader;
import java.io.PrintWriter;
import java.math.BigInteger;
import java.util.ArrayList;
import java.util.Arrays;
import java.util.BitSet;
import java.util.Calendar;
import java.util.Collections;
import java.util.Comparator;
import java.util.HashMap;
import java.util.HashSet;
import java.util.LinkedList;
import java.util.PriorityQueue;
import java.util.SortedSet;
import java.util.Stack;
import java.util.StringTokenizer;
import java.util.TreeMap;
import java.util.TreeSet;

/**
 * #
 * @author pttrung
 */
public class C_IndiaHack_2016 {

    public static long MOD = 1000000007;

    public static void main(String[] args) throws FileNotFoundException {
        // PrintWriter out = new PrintWriter(new FileOutputStream(new File(
        // "output.txt")));
        PrintWriter out = new PrintWriter(System.out);
        Scanner in = new Scanner();
        int n = in.nextInt();
        int[] data = new int[n];
        for (int i = 0; i < n; i++) {
            data[i] = in.nextInt();
        }

        int c = 0;
        int x = -1;
        int y = -1;
        for (int i = 0; i < n - 1; i++) {
            if (!check(i, data)) {

                if (x == -1) {
                    x = i;
                } else {
                    y = i;
                }
                c++;
            }

        }
        if (c > 2) {
            out.println(0);
        } else if (c == 2) {
            int tmp = data[x];
            data[x] = data[y];
            data[y] = tmp;
            if (check(x, data) && check(y, data)) {
                out.println(1);
            } else {
                out.println(0);
            }
        } else {
            int result = 0;
            for (int i = 0; i < n - 1; i++) {
                int tmp = data[x];
                data[x] = data[i];
                data[i] = tmp;
                if (check(i, data) && check(x, data) && check(i - 1, data)) {
                    //System.out.println(i + " " + x);
                    result++;
                }
                tmp = data[x];
                data[x] = data[i];
                data[i] = tmp;
                tmp = data[x + 1];
                data[x + 1] = data[i];
                data[i] = tmp;
                if (check(i, data) && check(x, data) && check(x + 1, data) && check(i - 1, data)) {
                    //System.out.println(i + " " + x);
                    result++;
                }
                tmp = data[x + 1];
                data[x + 1] = data[i];
                data[i] = tmp;
            }
            out.println(result);
        }
        out.close();
    }

    static boolean check(int index, int[] data) {
        if (index + 1 == data.length || index < 0) {
            return true;
        }
        if (index % 2 == 0) {
            return data[index] < data[index + 1];
        } else {
            return data[index] > data[index + 1];
        }
    }

    public static int[] KMP(String val) {
        int i = 0;
        int j = -1;
        int[] result = new int[val.length() + 1];
        result[0] = -1;
        while (i < val.length()) {
            while (j >= 0 && val.charAt(j) != val.charAt(i)) {
                j = result[j];
            }
            j++;
            i++;
            result[i] = j;
        }
        return result;

    }

    public static boolean nextPer(int[] data) {
        int i = data.length - 1;
        while (i > 0 && data[i] < data[i - 1]) {
            i--;
        }
        if (i == 0) {
            return false;
        }
        int j = data.length - 1;
        while (data[j] < data[i - 1]) {
            j--;
        }
        int temp = data[i - 1];
        data[i - 1] = data[j];
        data[j] = temp;
        Arrays.sort(data, i, data.length);
        return true;
    }

    public static int digit(long n) {
        int result = 0;
        while (n > 0) {
            n /= 10;
            result++;
        }
        return result;
    }

    public static double dist(long a, long b, long x, long y) {
        double val = (b - a) * (b - a) + (x - y) * (x - y);
        val = Math.sqrt(val);
        double other = x * x + a * a;
        other = Math.sqrt(other);
        return val + other;

    }

    public static class Point implements Comparable<Point> {

        int x, y;

        public Point(int start, int end) {
            this.x = start;
            this.y = end;
        }

        @Override
        public int hashCode() {
            int hash = 5;
            hash = 47 * hash + this.x;
            hash = 47 * hash + this.y;
            return hash;
        }

        @Override
        public boolean equals(Object obj) {
            if (obj == null) {
                return false;
            }
            if (getClass() != obj.getClass()) {
                return false;
            }
            final Point other = (Point) obj;
            if (this.x != other.x) {
                return false;
            }
            if (this.y != other.y) {
                return false;
            }
            return true;
        }

        @Override
        public int compareTo(Point o) {
            return x - o.x;
        }
    }

    public static class FT {

        long[] data;

        FT(int n) {
            data = new long[n];
        }

        public void update(int index, long value) {
            while (index < data.length) {
                data[index] += value;
                index += (index & (-index));
            }
        }

        public long get(int index) {
            long result = 0;
            while (index > 0) {
                result += data[index];
                index -= (index & (-index));
            }
            return result;

        }
    }

    public static long gcd(long a, long b) {
        if (b == 0) {
            return a;
        }
        return gcd(b, a % b);
    }

    public static long pow(long a, long b, long MOD) {
        if (b == 0) {
            return 1;
        }
        if (b == 1) {
            return a;
        }
        long val = pow(a, b / 2, MOD);
        if (b % 2 == 0) {
            return val * val % MOD;
        } else {
            return val * (val * a % MOD) % MOD;

        }
    }

    static class Scanner {

        BufferedReader br;
        StringTokenizer st;

        public Scanner() throws FileNotFoundException {
            // System.setOut(new PrintStream(new BufferedOutputStream(System.out), true));
            br = new BufferedReader(new InputStreamReader(System.in));
            //  br = new BufferedReader(new InputStreamReader(new FileInputStream(new File("input.txt"))));
        }

        public String next() {

            while (st == null || !st.hasMoreTokens()) {
                try {
                    st = new StringTokenizer(br.readLine());
                } catch (Exception e) {
                    throw new RuntimeException();
                }
            }
            return st.nextToken();
        }

        public long nextLong() {
            return Long.parseLong(next());
        }

        public int nextInt() {
            return Integer.parseInt(next());
        }

        public double nextDouble() {
            return Double.parseDouble(next());
        }

        public String nextLine() {
            st = null;
            try {
                return br.readLine();
            } catch (Exception e) {
                throw new RuntimeException();
            }
        }

        public boolean endLine() {
            try {
                String next = br.readLine();
                while (next != null && next.trim().isEmpty()) {
                    next = br.readLine();
                }
                if (next == null) {
                    return true;
                }
                st = new StringTokenizer(next);
                return st.hasMoreTokens();
            } catch (Exception e) {
                throw new RuntimeException();
            }
        }
    }
}


import java.io.BufferedReader;
import java.io.File;
import java.io.FileInputStream;
import java.io.FileNotFoundException;
import java.io.FileOutputStream;
import java.io.InputStreamReader;
import java.io.PrintWriter;
import java.math.BigInteger;
import java.util.ArrayList;
import java.util.Arrays;
import java.util.BitSet;
import java.util.Calendar;
import java.util.Collections;
import java.util.Comparator;
import java.util.HashMap;
import java.util.HashSet;
import java.util.LinkedList;
import java.util.PriorityQueue;
import java.util.SortedSet;
import java.util.Stack;
import java.util.StringTokenizer;
import java.util.TreeMap;
import java.util.TreeSet;

/**
 * #
 * @author pttrung
 */
public class C_IndiaHack_2016 {

    public static long MOD = 1000000007;

    public static void main(String[] args) throws FileNotFoundException {
        // PrintWriter out = new PrintWriter(new FileOutputStream(new File(
        // "output.txt")));
        PrintWriter out = new PrintWriter(System.out);
        Scanner in = new Scanner();
        int n = in.nextInt();
        int[] data = new int[n];
        for (int i = 0; i < n; i++) {
            data[i] = in.nextInt();
        }

        int c = 0;

        ArrayList<Integer> list = new ArrayList();
        for (int i = 0; i < n - 1; i++) {
            if (!check(i, data)) {

                list.add(i);
            }

        }

        if (list.size() > 10) {
            out.println(0);
        } else if (list.size() > 2) {
            int result = 0;
            for (int i = 0; i < list.size(); i++) {
                for (int j = i + 1; j < list.size(); j++) {
                    int x = list.get(i);
                    int y = list.get(j);
                    for (int k = -1; k < 2; k++) {
                        for (int h = -1; h < 2; h++) {
                            boolean ok = true;
                            swap(x + k, y + h, data);
                            for (int v : list) {
                                ok &= check(v, data);
                            }
                            if (ok && check(x + k, data) && check(y + h, data) && check(x + k - 1, data) && check(y + h - 1, data)) {
                                result++;
                            }
                            swap(x + k, y + h, data);
                        }
                    }
                }
            }
            out.println(result);
        } else if (list.size() == 2) {
            if (list.get(0) + 1 != list.get(1)) {
                int x = list.get(0);
                int y = list.get(1);
                int result = 0;
                for (int i = -1; i < 2; i++) {
                    for (int j = -1; j < 2; j++) {
                        swap(x + i, y + j, data);

                        if (check(x, data) && check(y, data) && check(x + i, data) && check(y + j, data) && check(x + i - 1, data) && check(y + j - 1, data)) {
                            result++;
                        }
                        swap(x + i, y + j, data);
                    }
                }
                out.println(result);
            } else {
                int x = list.get(1);
                int result = 0;
                for (int i = 0; i < n; i++) {
                    swap(x, i, data);
                    if (check(i, data) && check(x, data) && check(i - 1, data) && check(x - 1, data)) {
                        //System.out.println(i + " " + x);
                        result++;
                    }
                    swap(x, i, data);
                }
                out.println(result);
            }

        } else {
            // System.out.println(list);
            int x = list.get(0);
            int result = 0;
            for (int i = 0; i < n; i++) {

                swap(x, i, data);

                if (check(i, data) && check(x, data) && check(i - 1, data) && check(x - 1, data)) {

                    result++;
                }
                swap(x, i, data);

                if (i != x) {
                    swap(x + 1, i, data);
                    if (check(i, data) && check(x, data) && check(x + 1, data) && check(i - 1, data)) {

                        result++;
                    }
                    swap(x + 1, i, data);
                }

            }
            out.println(result);
        }
        out.close();
    }

    static void swap(int x, int y, int[] data) {
        if (x < 0 || y < 0 || x >= data.length || y >= data.length) {
            return;
        }
        int tmp = data[x];
        data[x] = data[y];
        data[y] = tmp;
    }

    static boolean check(int index, int[] data) {
        if (index + 1 >= data.length || index < 0) {
            return true;
        }
        if (index % 2 == 0) {
            return data[index] < data[index + 1];
        } else {
            return data[index] > data[index + 1];
        }
    }

    public static int[] KMP(String val) {
        int i = 0;
        int j = -1;
        int[] result = new int[val.length() + 1];
        result[0] = -1;
        while (i < val.length()) {
            while (j >= 0 && val.charAt(j) != val.charAt(i)) {
                j = result[j];
            }
            j++;
            i++;
            result[i] = j;
        }
        return result;

    }

    public static boolean nextPer(int[] data) {
        int i = data.length - 1;
        while (i > 0 && data[i] < data[i - 1]) {
            i--;
        }
        if (i == 0) {
            return false;
        }
        int j = data.length - 1;
        while (data[j] < data[i - 1]) {
            j--;
        }
        int temp = data[i - 1];
        data[i - 1] = data[j];
        data[j] = temp;
        Arrays.sort(data, i, data.length);
        return true;
    }

    public static int digit(long n) {
        int result = 0;
        while (n > 0) {
            n /= 10;
            result++;
        }
        return result;
    }

    public static double dist(long a, long b, long x, long y) {
        double val = (b - a) * (b - a) + (x - y) * (x - y);
        val = Math.sqrt(val);
        double other = x * x + a * a;
        other = Math.sqrt(other);
        return val + other;

    }

    public static class Point implements Comparable<Point> {

        int x, y;

        public Point(int start, int end) {
            this.x = start;
            this.y = end;
        }

        @Override
        public int hashCode() {
            int hash = 5;
            hash = 47 * hash + this.x;
            hash = 47 * hash + this.y;
            return hash;
        }

        @Override
        public boolean equals(Object obj) {
            if (obj == null) {
                return false;
            }
            if (getClass() != obj.getClass()) {
                return false;
            }
            final Point other = (Point) obj;
            if (this.x != other.x) {
                return false;
            }
            if (this.y != other.y) {
                return false;
            }
            return true;
        }

        @Override
        public int compareTo(Point o) {
            return x - o.x;
        }
    }

    public static class FT {

        long[] data;

        FT(int n) {
            data = new long[n];
        }

        public void update(int index, long value) {
            while (index < data.length) {
                data[index] += value;
                index += (index & (-index));
            }
        }

        public long get(int index) {
            long result = 0;
            while (index > 0) {
                result += data[index];
                index -= (index & (-index));
            }
            return result;

        }
    }

    public static long gcd(long a, long b) {
        if (b == 0) {
            return a;
        }
        return gcd(b, a % b);
    }

    public static long pow(long a, long b, long MOD) {
        if (b == 0) {
            return 1;
        }
        if (b == 1) {
            return a;
        }
        long val = pow(a, b / 2, MOD);
        if (b % 2 == 0) {
            return val * val % MOD;
        } else {
            return val * (val * a % MOD) % MOD;

        }
    }

    static class Scanner {

        BufferedReader br;
        StringTokenizer st;

        public Scanner() throws FileNotFoundException {
            // System.setOut(new PrintStream(new BufferedOutputStream(System.out), true));
            br = new BufferedReader(new InputStreamReader(System.in));
            //  br = new BufferedReader(new InputStreamReader(new FileInputStream(new File("input.txt"))));
        }

        public String next() {

            while (st == null || !st.hasMoreTokens()) {
                try {
                    st = new StringTokenizer(br.readLine());
                } catch (Exception e) {
                    throw new RuntimeException();
                }
            }
            return st.nextToken();
        }

        public long nextLong() {
            return Long.parseLong(next());
        }

        public int nextInt() {
            return Integer.parseInt(next());
        }

        public double nextDouble() {
            return Double.parseDouble(next());
        }

        public String nextLine() {
            st = null;
            try {
                return br.readLine();
            } catch (Exception e) {
                throw new RuntimeException();
            }
        }

        public boolean endLine() {
            try {
                String next = br.readLine();
                while (next != null && next.trim().isEmpty()) {
                    next = br.readLine();
                }
                if (next == null) {
                    return true;
                }
                st = new StringTokenizer(next);
                return st.hasMoreTokens();
            } catch (Exception e) {
                throw new RuntimeException();
            }
        }
    }
}


import java.io.BufferedReader;
import java.io.File;
import java.io.FileInputStream;
import java.io.FileNotFoundException;
import java.io.FileOutputStream;
import java.io.InputStreamReader;
import java.io.PrintWriter;
import java.math.BigInteger;
import java.util.ArrayList;
import java.util.Arrays;
import java.util.BitSet;
import java.util.Calendar;
import java.util.Collections;
import java.util.Comparator;
import java.util.HashMap;
import java.util.HashSet;
import java.util.LinkedList;
import java.util.PriorityQueue;
import java.util.SortedSet;
import java.util.Stack;
import java.util.StringTokenizer;
import java.util.TreeMap;
import java.util.TreeSet;

/**
 * #
 * @author pttrung
 */
public class C_IndiaHack_2016 {

    public static long MOD = 1000000007;

    public static void main(String[] args) throws FileNotFoundException {
        // PrintWriter out = new PrintWriter(new FileOutputStream(new File(
        // "output.txt")));
        PrintWriter out = new PrintWriter(System.out);
        Scanner in = new Scanner();
        int n = in.nextInt();
        int[] data = new int[n];
        for (int i = 0; i < n; i++) {
            data[i] = in.nextInt();
        }

        int c = 0;
        int x = -1;
        int y = -1;
        for (int i = 0; i < n - 1; i++) {
            if (!check(i, data)) {

                if (x == -1) {
                    x = i;
                } else {
                    y = i;
                }
                c++;
            }

        }
        if (c > 2) {
            out.println(0);
        } else if (c == 2) {
            int result = 0;
            for (int i = -1; i < 2; i++) {
                for (int j = -1; j < 2; j++) {
                    swap(x + i, y + j, data);

                    if (check(x, data) && check(y, data) && check(x + i, data) && check(y + j, data) && check(x + i - 1, data) && check(y + j - 1, data)) {
                        result++;
                    }
                    swap(x + i, y + j, data);
                }
            }
            out.println(result);

        } else {
            int result = 0;
            for (int i = 0; i < n - 1; i++) {
                swap(x, i, data);
                if (check(i, data) && check(x, data) && check(i - 1, data) && check(x - 1, data)) {
                    //System.out.println(i + " " + x);
                    result++;
                }
                swap(x, i, data);
                swap(x + 1, i, data);
                if (check(i, data) && check(x, data) && check(x + 1, data) && check(i - 1, data)) {
                    //System.out.println(i + " " + x);
                    result++;
                }
                swap(x + 1, i, data);

            }
            out.println(result);
        }
        out.close();
    }

    static void swap(int x, int y, int[] data) {
        if (x < 0 || y < 0 || x >= data.length || y >= data.length) {
            return;
        }
        int tmp = data[x];
        data[x] = data[y];
        data[y] = tmp;
    }

    static boolean check(int index, int[] data) {
        if (index + 1 >= data.length || index < 0) {
            return true;
        }
        if (index % 2 == 0) {
            return data[index] < data[index + 1];
        } else {
            return data[index] > data[index + 1];
        }
    }

    public static int[] KMP(String val) {
        int i = 0;
        int j = -1;
        int[] result = new int[val.length() + 1];
        result[0] = -1;
        while (i < val.length()) {
            while (j >= 0 && val.charAt(j) != val.charAt(i)) {
                j = result[j];
            }
            j++;
            i++;
            result[i] = j;
        }
        return result;

    }

    public static boolean nextPer(int[] data) {
        int i = data.length - 1;
        while (i > 0 && data[i] < data[i - 1]) {
            i--;
        }
        if (i == 0) {
            return false;
        }
        int j = data.length - 1;
        while (data[j] < data[i - 1]) {
            j--;
        }
        int temp = data[i - 1];
        data[i - 1] = data[j];
        data[j] = temp;
        Arrays.sort(data, i, data.length);
        return true;
    }

    public static int digit(long n) {
        int result = 0;
        while (n > 0) {
            n /= 10;
            result++;
        }
        return result;
    }

    public static double dist(long a, long b, long x, long y) {
        double val = (b - a) * (b - a) + (x - y) * (x - y);
        val = Math.sqrt(val);
        double other = x * x + a * a;
        other = Math.sqrt(other);
        return val + other;

    }

    public static class Point implements Comparable<Point> {

        int x, y;

        public Point(int start, int end) {
            this.x = start;
            this.y = end;
        }

        @Override
        public int hashCode() {
            int hash = 5;
            hash = 47 * hash + this.x;
            hash = 47 * hash + this.y;
            return hash;
        }

        @Override
        public boolean equals(Object obj) {
            if (obj == null) {
                return false;
            }
            if (getClass() != obj.getClass()) {
                return false;
            }
            final Point other = (Point) obj;
            if (this.x != other.x) {
                return false;
            }
            if (this.y != other.y) {
                return false;
            }
            return true;
        }

        @Override
        public int compareTo(Point o) {
            return x - o.x;
        }
    }

    public static class FT {

        long[] data;

        FT(int n) {
            data = new long[n];
        }

        public void update(int index, long value) {
            while (index < data.length) {
                data[index] += value;
                index += (index & (-index));
            }
        }

        public long get(int index) {
            long result = 0;
            while (index > 0) {
                result += data[index];
                index -= (index & (-index));
            }
            return result;

        }
    }

    public static long gcd(long a, long b) {
        if (b == 0) {
            return a;
        }
        return gcd(b, a % b);
    }

    public static long pow(long a, long b, long MOD) {
        if (b == 0) {
            return 1;
        }
        if (b == 1) {
            return a;
        }
        long val = pow(a, b / 2, MOD);
        if (b % 2 == 0) {
            return val * val % MOD;
        } else {
            return val * (val * a % MOD) % MOD;

        }
    }

    static class Scanner {

        BufferedReader br;
        StringTokenizer st;

        public Scanner() throws FileNotFoundException {
            // System.setOut(new PrintStream(new BufferedOutputStream(System.out), true));
            br = new BufferedReader(new InputStreamReader(System.in));
            //  br = new BufferedReader(new InputStreamReader(new FileInputStream(new File("input.txt"))));
        }

        public String next() {

            while (st == null || !st.hasMoreTokens()) {
                try {
                    st = new StringTokenizer(br.readLine());
                } catch (Exception e) {
                    throw new RuntimeException();
                }
            }
            return st.nextToken();
        }

        public long nextLong() {
            return Long.parseLong(next());
        }

        public int nextInt() {
            return Integer.parseInt(next());
        }

        public double nextDouble() {
            return Double.parseDouble(next());
        }

        public String nextLine() {
            st = null;
            try {
                return br.readLine();
            } catch (Exception e) {
                throw new RuntimeException();
            }
        }

        public boolean endLine() {
            try {
                String next = br.readLine();
                while (next != null && next.trim().isEmpty()) {
                    next = br.readLine();
                }
                if (next == null) {
                    return true;
                }
                st = new StringTokenizer(next);
                return st.hasMoreTokens();
            } catch (Exception e) {
                throw new RuntimeException();
            }
        }
    }
}


import java.io.BufferedReader;
import java.io.File;
import java.io.FileInputStream;
import java.io.FileNotFoundException;
import java.io.FileOutputStream;
import java.io.InputStreamReader;
import java.io.PrintWriter;
import java.math.BigInteger;
import java.util.ArrayList;
import java.util.Arrays;
import java.util.BitSet;
import java.util.Calendar;
import java.util.Collections;
import java.util.Comparator;
import java.util.HashMap;
import java.util.HashSet;
import java.util.LinkedList;
import java.util.PriorityQueue;
import java.util.SortedSet;
import java.util.Stack;
import java.util.StringTokenizer;
import java.util.TreeMap;
import java.util.TreeSet;

/**
 * #
 * @author pttrung
 */
public class C_IndiaHack_2016 {

    public static long MOD = 1000000007;

    public static void main(String[] args) throws FileNotFoundException {
        // PrintWriter out = new PrintWriter(new FileOutputStream(new File(
        // "output.txt")));
        PrintWriter out = new PrintWriter(System.out);
        Scanner in = new Scanner();
        int n = in.nextInt();
        int[] data = new int[n];
        for (int i = 0; i < n; i++) {
            data[i] = in.nextInt();
        }

        int c = 0;

        ArrayList<Integer> list = new ArrayList();
        for (int i = 0; i < n - 1; i++) {
            if (!check(i, data)) {

                list.add(i);
            }

        }
        if (list.size() > 2) {
            int result = 0;
            for (int i = 0; i < list.size(); i++) {
                for (int j = i + 1; j < list.size(); j++) {
                    int x = list.get(i);
                    int y = list.get(j);
                    for (int k = -1; k < 2; k++) {
                        for (int h = -1; h < 2; h++) {
                            boolean ok = true;
                            for (int v : list) {
                                ok &= check(v, data);
                            }
                            if (ok && check(x + i, data) && check(y + j, data) && check(x + i - 1, data) && check(y + j - 1, data)) {
                                result++;
                            }
                        }
                    }
                }
            }
            out.println(result);
        } else if (list.size() == 2) {
            int x = list.get(0);
            int y = list.get(1);
            int result = 0;
            for (int i = -1; i < 2; i++) {
                for (int j = -1; j < 2; j++) {
                    swap(x + i, y + j, data);

                    if (check(x, data) && check(y, data) && check(x + i, data) && check(y + j, data) && check(x + i - 1, data) && check(y + j - 1, data)) {
                        result++;
                    }
                    swap(x + i, y + j, data);
                }
            }
            out.println(result);

        } else {
            int x = list.get(0);
            int result = 0;
            for (int i = 0; i < n - 1; i++) {
                swap(x, i, data);
                if (check(i, data) && check(x, data) && check(i - 1, data) && check(x - 1, data)) {
                    //System.out.println(i + " " + x);
                    result++;
                }
                swap(x, i, data);
                swap(x + 1, i, data);
                if (check(i, data) && check(x, data) && check(x + 1, data) && check(i - 1, data)) {
                    //System.out.println(i + " " + x);
                    result++;
                }
                swap(x + 1, i, data);

            }
            out.println(result);
        }
        out.close();
    }

    static void swap(int x, int y, int[] data) {
        if (x < 0 || y < 0 || x >= data.length || y >= data.length) {
            return;
        }
        int tmp = data[x];
        data[x] = data[y];
        data[y] = tmp;
    }

    static boolean check(int index, int[] data) {
        if (index + 1 >= data.length || index < 0) {
            return true;
        }
        if (index % 2 == 0) {
            return data[index] < data[index + 1];
        } else {
            return data[index] > data[index + 1];
        }
    }

    public static int[] KMP(String val) {
        int i = 0;
        int j = -1;
        int[] result = new int[val.length() + 1];
        result[0] = -1;
        while (i < val.length()) {
            while (j >= 0 && val.charAt(j) != val.charAt(i)) {
                j = result[j];
            }
            j++;
            i++;
            result[i] = j;
        }
        return result;

    }

    public static boolean nextPer(int[] data) {
        int i = data.length - 1;
        while (i > 0 && data[i] < data[i - 1]) {
            i--;
        }
        if (i == 0) {
            return false;
        }
        int j = data.length - 1;
        while (data[j] < data[i - 1]) {
            j--;
        }
        int temp = data[i - 1];
        data[i - 1] = data[j];
        data[j] = temp;
        Arrays.sort(data, i, data.length);
        return true;
    }

    public static int digit(long n) {
        int result = 0;
        while (n > 0) {
            n /= 10;
            result++;
        }
        return result;
    }

    public static double dist(long a, long b, long x, long y) {
        double val = (b - a) * (b - a) + (x - y) * (x - y);
        val = Math.sqrt(val);
        double other = x * x + a * a;
        other = Math.sqrt(other);
        return val + other;

    }

    public static class Point implements Comparable<Point> {

        int x, y;

        public Point(int start, int end) {
            this.x = start;
            this.y = end;
        }

        @Override
        public int hashCode() {
            int hash = 5;
            hash = 47 * hash + this.x;
            hash = 47 * hash + this.y;
            return hash;
        }

        @Override
        public boolean equals(Object obj) {
            if (obj == null) {
                return false;
            }
            if (getClass() != obj.getClass()) {
                return false;
            }
            final Point other = (Point) obj;
            if (this.x != other.x) {
                return false;
            }
            if (this.y != other.y) {
                return false;
            }
            return true;
        }

        @Override
        public int compareTo(Point o) {
            return x - o.x;
        }
    }

    public static class FT {

        long[] data;

        FT(int n) {
            data = new long[n];
        }

        public void update(int index, long value) {
            while (index < data.length) {
                data[index] += value;
                index += (index & (-index));
            }
        }

        public long get(int index) {
            long result = 0;
            while (index > 0) {
                result += data[index];
                index -= (index & (-index));
            }
            return result;

        }
    }

    public static long gcd(long a, long b) {
        if (b == 0) {
            return a;
        }
        return gcd(b, a % b);
    }

    public static long pow(long a, long b, long MOD) {
        if (b == 0) {
            return 1;
        }
        if (b == 1) {
            return a;
        }
        long val = pow(a, b / 2, MOD);
        if (b % 2 == 0) {
            return val * val % MOD;
        } else {
            return val * (val * a % MOD) % MOD;

        }
    }

    static class Scanner {

        BufferedReader br;
        StringTokenizer st;

        public Scanner() throws FileNotFoundException {
            // System.setOut(new PrintStream(new BufferedOutputStream(System.out), true));
            br = new BufferedReader(new InputStreamReader(System.in));
            //  br = new BufferedReader(new InputStreamReader(new FileInputStream(new File("input.txt"))));
        }

        public String next() {

            while (st == null || !st.hasMoreTokens()) {
                try {
                    st = new StringTokenizer(br.readLine());
                } catch (Exception e) {
                    throw new RuntimeException();
                }
            }
            return st.nextToken();
        }

        public long nextLong() {
            return Long.parseLong(next());
        }

        public int nextInt() {
            return Integer.parseInt(next());
        }

        public double nextDouble() {
            return Double.parseDouble(next());
        }

        public String nextLine() {
            st = null;
            try {
                return br.readLine();
            } catch (Exception e) {
                throw new RuntimeException();
            }
        }

        public boolean endLine() {
            try {
                String next = br.readLine();
                while (next != null && next.trim().isEmpty()) {
                    next = br.readLine();
                }
                if (next == null) {
                    return true;
                }
                st = new StringTokenizer(next);
                return st.hasMoreTokens();
            } catch (Exception e) {
                throw new RuntimeException();
            }
        }
    }
}


import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStream;
import java.io.InputStreamReader;
import java.io.OutputStream;
import java.io.PrintWriter;
import java.util.Arrays;
import java.util.StringTokenizer;

public class Main {
	public static void main(String args[]) {
		InputStream intputStream = System.in;
		OutputStream outputStream = System.out;
		InputReader in = new InputReader(intputStream);
		PrintWriter out = new PrintWriter(outputStream);
		TaskC solver = new TaskC();
		solver.solve(in, out);
		out.close();
	}

	static class TaskC {
		public void solve(InputReader in, PrintWriter out) {
			int n = in.nextInt();
			int[] t = new int[n + 1];
			for (int i = 1; i <= n; ++i) {
				t[i] = in.nextInt();
			}
			int cnt = 0;
			int l = -1, r = -1, a = -1, b = -1;
			boolean flag = true;
			for (int i = 1; i < n; ++i) {
				if (i % 2 == 1) {
					if (t[i] >= t[i + 1]) {
						if (cnt == 0) {
							l = i;
							r = i;
							++cnt;
						} else if (cnt == 1) {
							if (i == r + 1) {
								++r;
								if ((r - l + 1) > 3) {
									flag = false;
									break;
								}
							} else {
								++cnt;
								a = i;
								b = i;
							}
						} else {
							if (i == b + 1) {
								++b;
								if ((b - a + 1) > 3) {
									flag = false;
									break;
								}
							} else {
								flag = false;
								break;
							}
						}
					}
				} else {
					if (t[i] <= t[i + 1]) {
						if (cnt == 0) {
							l = i;
							r = i;
							++cnt;
						} else if (cnt == 1) {
							if (i == r + 1) {
								++r;
								if ((r - l + 1) > 3) {
									flag = false;
									break;
								}
							} else {
								++cnt;
								a = i;
								b = i;
							}
						} else {
							if (i == b + 1) {
								++b;
								if ((b - a + 1) > 3) {
									flag = false;
									break;
								}
							} else {
								flag = false;
								break;
							}
						}
					}
				}
			}
			if (flag == false) {
				out.println(0);
			} else {
				Pair[] d = new Pair[1050000];
				int ans = 0;
				if (cnt == 2) {
					l = Math.max(1, l - 2);
					r = Math.min(n, r + 2);
					a = Math.max(1, a - 2);
					b = Math.min(n, b + 2);
					for (int i = l; i <= r; ++i) {
						for (int j = a; j <= b; ++j) {
							if (i == j) continue;
							int tmp = t[i];
							t[i] = t[j];
							t[j] = tmp;
							boolean mark = true;
							for (int k = Math.max(l - 1, 1); k <= Math.min(r, n - 1); ++k) {
								if (k % 2 == 1) {
									if (t[k] >= t[k + 1]) {
										mark = false;
										break;
									}
								} else {
									if (t[k] <= t[k + 1]) {
										mark = false;
										break;
									}
								}
							}
							for (int k = Math.max(a - 1, 1); k <= Math.min(b, n - 1); ++k) {
								if (k % 2 == 1) {
									if (t[k] >= t[k + 1]) {
										mark = false;
										break;
									}
								} else {
									if (t[k] <= t[k + 1]) {
										mark = false;
										break;
									}
								}
							}
							if (mark) {
								if (i > j) {
									d[ans] = new Pair(j, i);
									++ans;
								} else {
									d[ans] = new Pair(i, j);
									++ans;
								}
							}
							tmp = t[i];
							t[i] = t[j];
							t[j] = tmp;
						}
					}
				} else {
					l = Math.max(1, l - 2);
					r = Math.min(n, r + 2);
					for (int i = l; i <= r; ++i) {
						for (int j = 1; j <= n; ++j) {
							if (i == j) continue;
							int tmp = t[i];
							t[i] = t[j];
							t[j] = tmp;
							boolean mark = true;
							for (int k = Math.max(l - 1, 1); k <= Math.min(r, n - 1); ++k) {
								if (k % 2 == 1) {
									if (t[k] >= t[k + 1]) {
										mark = false;
										break;
									}
								} else {
									if (t[k] <= t[k + 1]) {
										mark = false;
										break;
									}
								}
							}
							a = Math.max(1, j - 2);
							b = Math.min(n, j + 2);
							for (int k = Math.max(a - 1, 1); k <= Math.min(b, n - 1); ++k) {
								if (k % 2 == 1) {
									if (t[k] >= t[k + 1]) {
										mark = false;
										break;
									}
								} else {
									if (t[k] <= t[k + 1]) {
										mark = false;
										break;
									}
								}
							}
							if (mark) {
								if (i > j) {
									d[ans] = new Pair(j, i);
									++ans;
								} else {
									d[ans] = new Pair(i, j);
									++ans;
								}
							}
							tmp = t[i];
							t[i] = t[j];
							t[j] = tmp;
						}
					}
				}
				Arrays.sort(d, 0, ans, (o1, o2) -> (o1.x == o2.x ? Integer.compare(o1.y, o2.y) : Integer.compare(o1.x, o2.x)));
				int res = ans;
				for (int i = 1; i < ans; ++i) {
					if (d[i].x == d[i - 1].x && d[i].y == d[i - 1].y) {
						--res;
					}
				}
				out.println(res);
			}
		}

		class Pair {
			int x, y;

			Pair(int x, int y) {
				this.x = x;
				this.y = y;
			}
		}
	}

	static class InputReader {
		public BufferedReader reader;
		public StringTokenizer tokenizer;

		public InputReader(InputStream stream) {
			reader = new BufferedReader(new InputStreamReader(stream), 32768);
			tokenizer = null;
		}

		public String next() {
			while (tokenizer == null || !tokenizer.hasMoreTokens()) {
				try {
					tokenizer = new StringTokenizer(reader.readLine());
				} catch (IOException e) {
					throw new RuntimeException(e);
				}
			}
			return tokenizer.nextToken();
		}

		public int nextInt() {
			return Integer.parseInt(next());
		}

		public double nextDouble() {
			return Double.parseDouble(next());
		}

		public long nextLong() {
			return Long.parseLong(next());
		}

		public String nextLine() {
			try {
				return reader.readLine();
			} catch (IOException e) {
				return null;
			}
		}
	}
}


// package codeforces.other2016.indiahacks2016;

import java.io.IOException;
import java.io.InputStream;
import java.io.PrintWriter;
import java.util.Arrays;
import java.util.HashSet;
import java.util.InputMismatchException;
import java.util.Set;

/**
 * Created by hama_du on 2016/03/19.
 */
public class Main {
    public static void main(String[] args) {
        InputReader in = new InputReader(System.in);
        PrintWriter out = new PrintWriter(System.out);

        int n = in.nextInt();
        int[] a = new int[n];
        for (int i = 0; i < n ; i++) {
            a[i] = in.nextInt();
        }

        Set<Long> okSet = new HashSet<>();
        for (int f = 0 ; f <= 1 ; f++) {
            boolean[] wrong = new boolean[n];
            int ct = 0;
            for (int i = 0; i < n-1; i++) {
                if (a[i] < a[i+1] && i % 2 == f) {
                } else if (a[i] > a[i+1] && i % 2 == 1-f) {
                } else {
                    wrong[i] = wrong[i+1] = true;
                    ct++;
                }
            }
            if (ct <= 4) {
                for (int i = 0; i < n; i++) {
                    if (wrong[i]) {
                        for (int j = 0; j < n; j++) {
                            if (i == j) {
                                continue;
                            }
                            swap(a, i, j);
                            if (confirm(a)) {
                                okSet.add(i*100000000L+j);
                            }
                            swap(a, i, j);
                        }
                    }
                }
            }
        }
        out.println(okSet.size() / 2);
        out.flush();
    }

    private static void swap(int[] a, int i, int j) {
        int tmp = a[i];
        a[i] = a[j];
        a[j] = tmp;
    }

    private static boolean confirm(int[] a) {
        for (int i = 0; i < a.length - 1; i++) {
            if (a[i] == a[i+1]) {
                return false;
            }
        }
        boolean less = a[0] > a[1];
        for (int i = 1 ; i < a.length-1 ; i++) {
            if (less) {
                if (a[i] >= a[i+1]) {
                    return false;
                }
            } else {
                if (a[i] <= a[i+1]) {
                    return false;
                }
            }
            less = !less;
        }
        return true;
    }

    static class InputReader {
        private InputStream stream;
        private byte[] buf = new byte[1024];
        private int curChar;
        private int numChars;

        public InputReader(InputStream stream) {
            this.stream = stream;
        }

        private int next() {
            if (numChars == -1)
                throw new InputMismatchException();
            if (curChar >= numChars) {
                curChar = 0;
                try {
                    numChars = stream.read(buf);
                } catch (IOException e) {
                    throw new InputMismatchException();
                }
                if (numChars <= 0)
                    return -1;
            }
            return buf[curChar++];
        }

        public char nextChar() {
            int c = next();
            while (isSpaceChar(c))
                c = next();
            if ('a' <= c && c <= 'z') {
                return (char) c;
            }
            if ('A' <= c && c <= 'Z') {
                return (char) c;
            }
            throw new InputMismatchException();
        }

        public String nextToken() {
            int c = next();
            while (isSpaceChar(c))
                c = next();
            StringBuilder res = new StringBuilder();
            do {
                res.append((char) c);
                c = next();
            } while (!isSpaceChar(c));
            return res.toString();
        }

        public int nextInt() {
            int c = next();
            while (isSpaceChar(c))
                c = next();
            int sgn = 1;
            if (c == '-') {
                sgn = -1;
                c = next();
            }
            int res = 0;
            do {
                if (c < '0' || c > '9')
                    throw new InputMismatchException();
                res *= 10;
                res += c-'0';
                c = next();
            } while (!isSpaceChar(c));
            return res * sgn;
        }

        public long nextLong() {
            int c = next();
            while (isSpaceChar(c))
                c = next();
            long sgn = 1;
            if (c == '-') {
                sgn = -1;
                c = next();
            }
            long res = 0;
            do {
                if (c < '0' || c > '9')
                    throw new InputMismatchException();
                res *= 10;
                res += c-'0';
                c = next();
            } while (!isSpaceChar(c));
            return res * sgn;
        }

        public boolean isSpaceChar(int c) {
            return c == ' ' || c == '\n' || c == '\r' || c == '\t' || c == -1;
        }

        public interface SpaceCharFilter {
            public boolean isSpaceChar(int ch);
        }
    }

    static void debug(Object... o) {
        System.err.println(Arrays.deepToString(o));
    }
}


// package codeforces.other2016.indiahacks2016;

import java.io.IOException;
import java.io.InputStream;
import java.io.PrintWriter;
import java.util.Arrays;
import java.util.HashSet;
import java.util.InputMismatchException;
import java.util.Set;

/**
 * Created by hama_du on 2016/03/19.
 */
public class Main {
    public static void main(String[] args) {
        InputReader in = new InputReader(System.in);
        PrintWriter out = new PrintWriter(System.out);

        int n = in.nextInt();
        int[] a = new int[n];
        for (int i = 0; i < n ; i++) {
            a[i] = in.nextInt();
        }

        Set<Long> okSet = new HashSet<>();
        boolean[] wrong = new boolean[n];
        int ct = 0;
        for (int i = 0; i < n-1; i++) {
            if (a[i] < a[i+1] && i % 2 == 0) {
            } else if (a[i] > a[i+1] && i % 2 == 1) {
            } else {
                wrong[i] = wrong[i+1] = true;
                ct++;
            }
        }
        if (ct <= 2) {
            for (int i = 0; i < n; i++) {
                if (wrong[i]) {
                    for (int j = 0; j < n; j++) {
                        if (i == j) {
                            continue;
                        }
                        swap(a, i, j);
                        if (confirm(a)) {
                            int ii = Math.min(i, j);
                            int jj = Math.max(i, j);
                            okSet.add(ii*100000000L+jj);
                        }
                        swap(a, i, j);
                    }
                }
            }
        }

        out.println(okSet.size());
        out.flush();
    }

    private static void swap(int[] a, int i, int j) {
        int tmp = a[i];
        a[i] = a[j];
        a[j] = tmp;
    }

    private static boolean confirm(int[] a) {
        for (int i = 0; i < a.length - 1; i++) {
            if (a[i] == a[i+1]) {
                return false;
            }
        }
        boolean less = true;
        for (int i = 0 ; i < a.length-1 ; i++) {
            if (less) {
                if (a[i] >= a[i+1]) {
                    return false;
                }
            } else {
                if (a[i] <= a[i+1]) {
                    return false;
                }
            }
            less = !less;
        }
        return true;
    }

    static class InputReader {
        private InputStream stream;
        private byte[] buf = new byte[1024];
        private int curChar;
        private int numChars;

        public InputReader(InputStream stream) {
            this.stream = stream;
        }

        private int next() {
            if (numChars == -1)
                throw new InputMismatchException();
            if (curChar >= numChars) {
                curChar = 0;
                try {
                    numChars = stream.read(buf);
                } catch (IOException e) {
                    throw new InputMismatchException();
                }
                if (numChars <= 0)
                    return -1;
            }
            return buf[curChar++];
        }

        public char nextChar() {
            int c = next();
            while (isSpaceChar(c))
                c = next();
            if ('a' <= c && c <= 'z') {
                return (char) c;
            }
            if ('A' <= c && c <= 'Z') {
                return (char) c;
            }
            throw new InputMismatchException();
        }

        public String nextToken() {
            int c = next();
            while (isSpaceChar(c))
                c = next();
            StringBuilder res = new StringBuilder();
            do {
                res.append((char) c);
                c = next();
            } while (!isSpaceChar(c));
            return res.toString();
        }

        public int nextInt() {
            int c = next();
            while (isSpaceChar(c))
                c = next();
            int sgn = 1;
            if (c == '-') {
                sgn = -1;
                c = next();
            }
            int res = 0;
            do {
                if (c < '0' || c > '9')
                    throw new InputMismatchException();
                res *= 10;
                res += c-'0';
                c = next();
            } while (!isSpaceChar(c));
            return res * sgn;
        }

        public long nextLong() {
            int c = next();
            while (isSpaceChar(c))
                c = next();
            long sgn = 1;
            if (c == '-') {
                sgn = -1;
                c = next();
            }
            long res = 0;
            do {
                if (c < '0' || c > '9')
                    throw new InputMismatchException();
                res *= 10;
                res += c-'0';
                c = next();
            } while (!isSpaceChar(c));
            return res * sgn;
        }

        public boolean isSpaceChar(int c) {
            return c == ' ' || c == '\n' || c == '\r' || c == '\t' || c == -1;
        }

        public interface SpaceCharFilter {
            public boolean isSpaceChar(int ch);
        }
    }

    static void debug(Object... o) {
        System.err.println(Arrays.deepToString(o));
    }
}


// package codeforces.other2016.indiahacks2016;

import java.io.IOException;
import java.io.InputStream;
import java.io.PrintWriter;
import java.util.*;

/**
 * Created by hama_du on 2016/03/19.
 */
public class Main {
    public static void main(String[] args) {
        InputReader in = new InputReader(System.in);
        PrintWriter out = new PrintWriter(System.out);

        int n = in.nextInt();
        int[] a = new int[n];
        for (int i = 0; i < n ; i++) {
            a[i] = in.nextInt();
        }

        Set<Long> okSet = new HashSet<>();
        boolean[] wrong = new boolean[n];
        int ct = 0;

        Set<Integer> fixPos = new HashSet<>();
        for (int i = 0; i < n-1; i++) {
            if (a[i] < a[i+1] && i % 2 == 0) {
            } else if (a[i] > a[i+1] && i % 2 == 1) {
            } else {
                fixPos.add(i);
                wrong[i] = wrong[i+1] = true;
                ct++;
            }
        }
        if (ct <= 4) {
            for (int i = 0; i < n; i++) {
                if (wrong[i]) {
                    for (int j = 0; j < n; j++) {
                        if (i == j) {
                            continue;
                        }
                        Set<Integer> confirmPos = new HashSet<>(fixPos);
                        confirmPos.add(i);
                        confirmPos.add(j);

                        swap(a, i, j);
                        if (confirm(a, confirmPos)) {
                            int ii = Math.min(i, j);
                            int jj = Math.max(i, j);
                            okSet.add(ii*100000000L+jj);
                        }
                        swap(a, i, j);
                    }
                }
            }
        }

        out.println(okSet.size());
        out.flush();
    }

    private static void swap(int[] a, int i, int j) {
        int tmp = a[i];
        a[i] = a[j];
        a[j] = tmp;
    }

    private static boolean confirm(int[] a, Set<Integer> fixPos) {
        for (int p : fixPos) {
            for (int d = p-2 ; d <= p+2 ; d++) {
                if (d < 0 || d >= a.length-1) {
                    continue;
                }
                if (d % 2 == 0) {
                    if (a[d] >= a[d+1]) {
                        return false;
                    }
                } else {
                    if (a[d] <= a[d+1]) {
                        return false;
                    }
                }
            }
        }
        return true;
    }

    static class InputReader {
        private InputStream stream;
        private byte[] buf = new byte[1024];
        private int curChar;
        private int numChars;

        public InputReader(InputStream stream) {
            this.stream = stream;
        }

        private int next() {
            if (numChars == -1)
                throw new InputMismatchException();
            if (curChar >= numChars) {
                curChar = 0;
                try {
                    numChars = stream.read(buf);
                } catch (IOException e) {
                    throw new InputMismatchException();
                }
                if (numChars <= 0)
                    return -1;
            }
            return buf[curChar++];
        }

        public char nextChar() {
            int c = next();
            while (isSpaceChar(c))
                c = next();
            if ('a' <= c && c <= 'z') {
                return (char) c;
            }
            if ('A' <= c && c <= 'Z') {
                return (char) c;
            }
            throw new InputMismatchException();
        }

        public String nextToken() {
            int c = next();
            while (isSpaceChar(c))
                c = next();
            StringBuilder res = new StringBuilder();
            do {
                res.append((char) c);
                c = next();
            } while (!isSpaceChar(c));
            return res.toString();
        }

        public int nextInt() {
            int c = next();
            while (isSpaceChar(c))
                c = next();
            int sgn = 1;
            if (c == '-') {
                sgn = -1;
                c = next();
            }
            int res = 0;
            do {
                if (c < '0' || c > '9')
                    throw new InputMismatchException();
                res *= 10;
                res += c-'0';
                c = next();
            } while (!isSpaceChar(c));
            return res * sgn;
        }

        public long nextLong() {
            int c = next();
            while (isSpaceChar(c))
                c = next();
            long sgn = 1;
            if (c == '-') {
                sgn = -1;
                c = next();
            }
            long res = 0;
            do {
                if (c < '0' || c > '9')
                    throw new InputMismatchException();
                res *= 10;
                res += c-'0';
                c = next();
            } while (!isSpaceChar(c));
            return res * sgn;
        }

        public boolean isSpaceChar(int c) {
            return c == ' ' || c == '\n' || c == '\r' || c == '\t' || c == -1;
        }

        public interface SpaceCharFilter {
            public boolean isSpaceChar(int ch);
        }
    }

    static void debug(Object... o) {
        System.err.println(Arrays.deepToString(o));
    }
}