Polycarpus loves lucky numbers. Everybody knows that lucky numbers are positive integers, whose decimal representation (without leading zeroes) contain only the lucky digits x and y. For example, if x = 4, and y = 7, then numbers 47, 744, 4 are lucky.

Let's call a positive integer a undoubtedly lucky, if there are such digits x and y (0 ≤ x, y ≤ 9), that the decimal representation of number a (without leading zeroes) contains only digits x and y.

Polycarpus has integer n. He wants to know how many positive integers that do not exceed n, are undoubtedly lucky. Help him, count this number.

Input

The first line contains a single integer n (1 ≤ n ≤ 109) — Polycarpus's number.

Output

Print a single integer that says, how many positive integers that do not exceed n are undoubtedly lucky.

Examples

Input

10


Output

10


Input

123


Output

113

Note

In the first test sample all numbers that do not exceed 10 are undoubtedly lucky.

In the second sample numbers 102, 103, 104, 105, 106, 107, 108, 109, 120, 123 are not undoubtedly lucky.
import java.util.*;
import java.io.*;

public class CF1 implements Runnable {

    static FastReader sc;
    static PrintWriter out;
    static int mod = 1000000007, inf = (int) 1e9, minf = -(int) 1e9;
    static long infL = (long) 1e18, minfL = -(long) 1e18;

    public static void main(String[] args) {
        new Thread(null, new CF1(), "coderrohan14", 1 << 26).start();
    }

    @Override
    public void run() {
        try {
            ioSetup();
        } catch (IOException e) {
            return;
        }
    }

    public static void ioSetup() throws IOException {
        if (System.getProperty("ONLINE_JUDGE") == null) {
            File f1 = new File("input.txt");
            File f2 = new File("output.txt");
            Reader r = new FileReader(f1);
            sc = new FastReader(r);
            out = new PrintWriter(f2);
            double prev = System.currentTimeMillis();
            solve();
            out.println("\n\nExecuted in : " + ((System.currentTimeMillis() - prev) / 1e3) + " sec");
        } else {
            sc = new FastReader(new InputStreamReader(System.in));
            out = new PrintWriter(System.out);
            solve();
        }
        out.flush();
        out.close();
    }

    static int n;
    static TreeSet<Long> ts;

    static void solve() {
        // int t = sc.nextInt();
        // StringBuilder ans = new StringBuilder("");
        // while (t-- > 0) {

        // }
        // out.println(ans);
        n = sc.nextInt();
        ts = new TreeSet<>();
        for (int i = 0; i <= 9; i++) {
            for (int j = i + 1; j <= 9; j++) {
                helper(i, j, -1);
            }
        }
        // out.println(ts);
        long num = ts.floor((long) n);
        int c = 0;
        for (Long e : ts) {
            if (e > num)
                break;
            c++;
        }
        out.println(c);
    }

    static void helper(int a, int b, long num) {
        if (num == -1) {
            if (a == 0) {
                helper(a, b, b);
            } else {
                helper(a, b, a);
                helper(a, b, b);
            }
            return;
        }
        if (num > n)
            return;
        ts.add(num);
        helper(a, b, (num * 10) + a);
        helper(a, b, (num * 10) + b);
    }

    /****************************************************************************************************************************************************************************************/

    public static int log2(int N) {
        int result = (int) (Math.log(N) / Math.log(2));
        return result;
    }

    static long modInverse(long a, int mod) {
        long g = gcd(a, mod);
        if (g != 1)
            return -1;
        else {
            return modPower(a, mod - 2L, mod);
        }
    }

    static long modPower(long x, long y, int mod) {
        long res = 1;
        x = x % mod;
        if (x == 0)
            return 0;
        while (y > 0) {
            if ((y & 1) != 0)
                res = (res * x) % mod;
            y = y >> 1;
            x = (x * x) % mod;
        }
        return res;
    }

    static int gcd(int a, int b) {
        int tmp = 0;
        while (b != 0) {
            tmp = b;
            b = a % b;
            a = tmp;
        }
        return a;
    }

    static long gcd(long a, long b) {
        long tmp = 0;
        while (b != 0) {
            tmp = b;
            b = a % b;
            a = tmp;
        }
        return a;
    }

    static boolean isPrime(long n) {
        if (n == 2 || n == 3)
            return true;
        if (n % 2 == 0)
            return false;
        for (long i = 3; i * i <= n; i += 2) {
            if (n % i == 0)
                return false;
        }
        return n != 1;
    }

    static boolean isPerfectSquare(long x) {
        long sqrt = (long) Math.sqrt(x);
        return (sqrt * sqrt) == x;
    }

    static int digitsCount(long x) {
        return (int) Math.floor(Math.log10(x)) + 1;
    }

    static boolean isPowerTwo(long n) {
        return (n & n - 1) == 0;
    }

    static void sieve(boolean[] prime, int n) { // Sieve Of Eratosthenes
        for (int i = 1; i <= n; i++) {
            prime[i] = true;
        }
        for (int i = 2; i * i <= n; i++) {
            if (prime[i]) {
                for (int j = 2; i * j <= n; j++) {
                    prime[i * j] = false;
                }
            }
        }
    }

    static long nCr(long n, long r) { // Combinations
        if (n < r)
            return 0;
        if (r > n - r) { // because nCr(n, r) == nCr(n, n - r)
            r = n - r;
        }
        long ans = 1L;
        for (long i = 0; i < r; i++) {
            ans *= (n - i);
            ans /= (i + 1);
        }
        return ans;
    }

    static int floor(int[] a, int v) {
        int l = 0, h = a.length - 1;
        while (l < h) {
            int mid = (l + h) / 2;
            if (a[mid] == v)
                return mid;
            if (v < a[mid])
                h = mid;
            else {
                if (mid + 1 < h && a[mid + 1] < v)
                    l = mid + 1;
                else
                    return mid;
            }
        }
        return a[l] <= v ? l : -1;
    }

    static int floor(long[] a, long v) {
        int l = 0, h = a.length - 1;
        while (l < h) {
            int mid = (l + h) / 2;
            if (a[mid] == v)
                return mid;
            if (v < a[mid])
                h = mid;
            else {
                if (mid + 1 < h && a[mid + 1] < v)
                    l = mid + 1;
                else
                    return mid;
            }
        }
        return a[l] <= v ? l : -1;
    }

    static int ceil(int[] a, int v) {
        int l = 0, h = a.length - 1;
        while (l < h) {
            int mid = (l + h) / 2;
            if (a[mid] == v)
                return mid;
            if (a[mid] < v)
                l = mid + 1;
            else
                h = mid;
        }
        return a[h] >= v ? h : -1;
    }

    static int ceil(long[] a, long v) {
        int l = 0, h = a.length - 1;
        while (l < h) {
            int mid = (l + h) / 2;
            if (a[mid] == v)
                return mid;
            if (a[mid] < v)
                l = mid + 1;
            else
                h = mid;
        }
        return a[h] >= v ? h : -1;
    }

    static long catalan(int n) { // n-th Catalan Number
        long c = nCr(2 * n, n);
        return c / (n + 1);
    }

    static class Pair implements Comparable<Pair> { // Pair Class
        long x;
        long y;

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

        @Override
        public boolean equals(Object o) {
            if (this == o) {
                return true;
            }
            if (!(o instanceof Pair)) {
                return false;
            }

            Pair pair = (Pair) o;

            if (x != pair.x) {
                return false;
            }
            if (y != pair.y) {
                return false;
            }

            return true;
        }

        @Override
        public int hashCode() {
            long result = x;
            result = 31 * result + y;
            return (int) result;
        }

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

    static class Trip { // Triplet Class
        long x;
        long y;
        long z;

        Trip(long x, long y, long z) {
            this.x = x;
            this.y = y;
            this.z = z;
        }

        @Override
        public boolean equals(Object o) {
            if (this == o) {
                return true;
            }
            if (!(o instanceof Trip)) {
                return false;
            }

            Trip trip = (Trip) o;

            if (x != trip.x) {
                return false;
            }
            if (y != trip.y) {
                return false;
            }
            if (z != trip.z) {
                return false;
            }
            return true;
        }

        @Override
        public int hashCode() {
            long result = 62 * x + 31 * y + z;
            return (int) result;
        }
    }

    /**************************************************************************************************************************************************************************************/

    static class FastReader {
        BufferedReader br;
        StringTokenizer st;

        public FastReader(Reader r) {
            br = new BufferedReader(r);
        }

        String next() {
            while (st == null || !st.hasMoreElements()) {
                try {
                    st = new StringTokenizer(br.readLine());
                } catch (IOException e) {
                    e.printStackTrace();
                }
            }
            return st.nextToken();
        }

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

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

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

        int[] readArrayI(int n) {
            int[] arr = new int[n];
            for (int i = 0; i < n; i++) {
                arr[i] = sc.nextInt();
            }
            return arr;
        }

        long[] readArrayL(int n) {
            long[] arr = new long[n];
            for (int i = 0; i < n; i++) {
                arr[i] = sc.nextLong();
            }
            return arr;
        }

        String nextLine() {
            String str = "";
            try {
                str = br.readLine();
            } catch (IOException e) {
                e.printStackTrace();
            }
            return str;
        }

        boolean hasNext() {
            if (st != null && st.hasMoreTokens()) {
                return true;
            }
            String tmp;
            try {
                br.mark(1000);
                tmp = br.readLine();
                if (tmp == null) {
                    return false;
                }
                br.reset();
            } catch (IOException e) {
                return false;
            }
            return true;
        }
    }

    /*
     * ASCII Range--->(A-Z)--->[65,90]<<::>>(a-z)--->[97,122]
     */
    /******************************************************************************************************************/

    static void printArray(int[] arr) {
        out.print("[");
        for (int i = 0; i < arr.length; i++) {
            if (i < arr.length - 1)
                out.print(arr[i] + ",");
            else
                out.print(arr[i]);
        }
        out.print("]");
        out.println();
    }

    static void printArray(long[] arr) {
        out.print("[");
        for (int i = 0; i < arr.length; i++) {
            if (i < arr.length - 1)
                out.print(arr[i] + ",");
            else
                out.print(arr[i]);
        }
        out.print("]");
        out.println();
    }

    static void printArray(double[] arr) {
        out.print("[");
        for (int i = 0; i < arr.length; i++) {
            if (i < arr.length - 1)
                out.print(arr[i] + ",");
            else
                out.print(arr[i]);
        }
        out.print("]");
        out.println();
    }
    /**********************************************************************************************************************/
}