Wilbur the pig is tinkering with arrays again. He has the array a1, a2, ..., an initially consisting of n zeros. At one step, he can choose any index i and either add 1 to all elements ai, ai + 1, ... , an or subtract 1 from all elements ai, ai + 1, ..., an. His goal is to end up with the array b1, b2, ..., bn. 

Of course, Wilbur wants to achieve this goal in the minimum number of steps and asks you to compute this value.

Input

The first line of the input contains a single integer n (1 ≤ n ≤ 200 000) — the length of the array ai. Initially ai = 0 for every position i, so this array is not given in the input.

The second line of the input contains n integers b1, b2, ..., bn ( - 109 ≤ bi ≤ 109).

Output

Print the minimum number of steps that Wilbur needs to make in order to achieve ai = bi for all i.

Examples

Input

5
1 2 3 4 5


Output

5

Input

4
1 2 2 1


Output

3

Note

In the first sample, Wilbur may successively choose indices 1, 2, 3, 4, and 5, and add 1 to corresponding suffixes.

In the second sample, Wilbur first chooses indices 1 and 2 and adds 1 to corresponding suffixes, then he chooses index 4 and subtract 1.

import java.awt.Point;
import java.awt.geom.Line2D;
import java.io.BufferedReader;
import java.io.File;
import java.io.OutputStream;
import java.io.IOException;
import java.io.InputStreamReader;
import java.io.PrintWriter;
import java.security.GuardedObject;
import java.util.ArrayList;
import java.util.Arrays;
import java.util.Collections;
import java.util.Comparator;
import java.util.HashMap;
import java.util.HashSet;
import java.util.InputMismatchException;
import java.util.LinkedList;
import java.util.List;
import java.util.PriorityQueue;
import java.util.Queue;
import java.util.Scanner;
import java.util.Stack;
import java.util.StringTokenizer;
import java.util.TreeMap;
import java.util.TreeSet;
import java.io.InputStream;
import java.math.BigInteger;








/**
 * Built using CHelper plug-in
 * Actual solution is at the top
 */
public class Main {
    public static void main(String[] args) throws IOException {
        InputStream inputStream = System.in;
        OutputStream outputStream = System.out;
        FastScanner in = new FastScanner(inputStream);
        PrintWriter out = new PrintWriter(outputStream);
        TaskC solver = new TaskC();
        long var=System.currentTimeMillis();
        solver.solve(1, in, out);
        /*if(System.getProperty("ONLINE_JUDGE")==null){
            out.println("["+(double)(System.currentTimeMillis()-var)/1000+"]");
        }*/
        out.close();
    }
}
class Pair {
    long x,y,index;
    Pair(long x,long y,int index){
        this.x=x;
        this.y=y;
        this.index=index;
    }
    public String toString(){
        return this.x+" "+this.y+" ";
    }
    
}
class tupple{
    long x,y,z;
    ArrayList<String> list=new ArrayList<>();
    tupple(long x,long y,long z){
        this.x=x;
        this.y=y;
        this.z=z;
    }
    tupple(tupple cl){
        this.x=cl.x;
        this.y=cl.y;
        this.z=cl.z;
        this.list=cl.list;
    }
}
class Edge{
    int u;
    int v;
    int time;
    long cost;
    public Edge(int u,int v){
        this.u=u;
        this.v=v;
        time=Integer.MAX_VALUE;
    }
    public int other(int x){
        if(u==x)return v;
        return u;
    }
}
class Ss{
    Integer a[]=new Integer[3];
    Ss(Integer a[]){
        this.a=a;
        
    }
    public int hashCode(){
        return a[0].hashCode()+a[1].hashCode()+a[2].hashCode();
    }
    public boolean equals(Object o){
        Ss x=(Ss)o;
        for(int i=0;i<3;i++){
            if(x.a[i]!=this.a[i]){
                return false;
            }
        }
        return true;
        
    }
}
class queary{
    int type;
    int l;
    int r;
    int index;
    queary(int type,int l,int r){
        this.type=type;
        this.l=l;
        this.r=r;
    }
}
class boat implements Comparable<boat>{
    int capacity;
    int index;
    boat(int capacity,int index)
    {
        this.capacity=capacity;
        this.index=index;
    }
    @Override
    public int compareTo(boat o) {
        // TODO Auto-generated method stub
        return this.capacity-o.capacity;
    }
}
class angle{
    double x,y,angle;
    int index;
    angle(int x,int y,double angle){
        this.x=x;
        this.y=y;
        this.angle=angle;
    }
}
class TaskC {
    static long mod=(long)(1e9+7);
//    SegTree tree;
    //    int min[];
    /*static int prime_len=100001;
    static int prime[]=new int[prime_len];
    static ArrayList<Integer> primes=new ArrayList<>();
    static ArrayList<Integer> list=new ArrayList<>();
    static{ 
        //System.out.println("lifhgifwrek");
        for(int i=2;i<=Math.sqrt(prime.length);i++){
            for(int j=i*i;j<prime.length;j+=i){
                
                prime[j]=i;
                
            }
        }
        for(int i=2;i<prime.length;i++){
            if(prime[i]==0){
                list.add(i);
            }
            
        }
    //  System.out.println("end");
        
    //  prime[0]=true;
    //  prime[1]=1;
    }
    /*
     *  long pp[]=new long[10000001];
            pp[0]=0;
            pp[1]=1;
            for(int i=2;i<pp.length;i++){
                if(prime[i]!=0){
                    int gcd=(int)greatestCommonDivisor(i/prime[i], prime[i]);
                    pp[i]=(pp[i/prime[i]]*pp[prime[i]]*gcd)/pp[(int)gcd];
                }
                else
                    pp[i]=i-1;
            }
        
     * */
    
            public void solve(int testNumber, FastScanner in, PrintWriter out) throws IOException {
                
                    int n=in.nextInt();
                    long a[]=new long[n];
                    
                    for(int i=0;i<n;i++){
                        a[i]=in.nextLong(); 
                    }
                    long x=0;
                    long ans=0;
                    for(int i=0;i<n;i++){
                        long diff=a[i]-x;
                        x+=diff;
                    //  out.println(diff);
                        ans+=Math.abs(diff);
                    }
                    out.println(ans);
            
            }
            static class pairs{
                String company,color;
                String type;
                boolean visit=false;
                pairs(String company,String color,String type){
                    this.company=company;
                    this.color=color;
                    this.type=type;
                }
            }
        BigInteger BMOD=BigInteger.valueOf(mod);
        private long inv(long q) {
            return BigInteger.valueOf(q).modInverse(BMOD).longValue();
        }

            static void dfs(List<Integer>[] graph, boolean[] used, List<Integer> res, int u) {
            used[u] = true;
            for (int v : graph[u])
              if (!used[v])
                dfs(graph, used, res, v);
            res.add(u);
          }

          public static List<Integer> topologicalSort(List<Integer>[] graph) {
            int n = graph.length;
            boolean[] used = new boolean[n];
            List<Integer> res = new ArrayList<>();
            for (int i = n-1; i >0; i--)
              if (!used[i])
                dfs(graph, used, res, i);
            Collections.reverse(res);
            return res;
          }
        
        public static long[][] mulmatrix(long m1[][],long m2[][],long mod){
            long ans[][]=new long[m1.length][m2[0].length];
            for(int i=0;i<m1.length;i++){
                for(int j=0;j<m2[0].length;j++){
                    for(int k=0;k<m1.length;k++){
                        ans[i][j]+=(m1[i][k]*m2[k][j]);
                        ans[i][j]%=mod;
                    }
                }
            }
            return ans;
        }
        public static long[][] matrixexpo(long m[][],String n,long mod){
            if(n.equals("1")){
                return m.clone(); 
            }
            if(n.equals("10")){
                return mulmatrix(m, m , mod);
            }
            else{
                long temp [][]=matrixexpo(m,n.substring(0,n.length()-1),mod);
                temp=mulmatrix(temp, temp, mod);
                if(n.charAt(n.length()-1)=='0')return temp;
                else return mulmatrix(temp, m,mod);
            }
        }
        public static boolean isCompatible(long x[],long y[]){
            
            for(int i=0;i<x.length-1;i++){
                if(x[i]==y[i] && x[i+1]==y[i+1] && x[i]==x[i+1] && y[i]==y[i+1]){
                    return false;
                }
            }
            return true;
        }
        
        int phi(int n) {
            int res = n;
            for (int i = 2; i * i <= n; ++i) {
                if (n % i == 0) {
                    while (n % i == 0) {
                        n /= i;
                    }
                    res -= res / i;
                }
            }
            if (n != 1) {
                res -= res / n;
            }
            return res;
        }
        long pow(long x,long y,long mod){
            if(y<=0){
                return 1;
            }
            if(y==1){
                return x%mod;
            }
            long temp=pow(x,y/2,mod);
            if(y%2==0){
                return (temp*temp)%mod;
            }
            else{
                return (((temp*temp)%mod)*x)%mod;
            }
        }
        
/*      long DP(int id,int mask){
            //System.out.println("hi"+dp[id][mask]+" "+id+" "+Integer.toBinaryString(mask));
            if(id==0 && mask==0){
                dp[0][mask]=1;
                return 1;
            }
            else if(id==0){
                dp[0][mask]=0;
                return 0;
            }
            if(dp[id][mask]!=-1){
            
                return dp[id][mask];
            }
            long ans=0;
            for(int i=0;i<n;i++){
                if((mask & (1<<i))!=0 && c[i][id]>=1){
                        ans+=DP(id-1,mask ^ (1 << i));
                        ans%=mod;
                }
            }
            ans+=DP(id-1,mask);
            ans%=mod;
            dp[id][mask]=ans;
            return ans;
        }*/
            static long greatestCommonDivisor (long m, long n){
                    long x;
                    long y;
                    while(m%n != 0){
                        x = n;
                        y = m%n;
                        m = x;
                        n = y;
                    }
                    return n;
                }
                long no_of_primes(long m,long n,long k){
                    long count=0,i,j;
                    int primes []=new int[(int)(n-m+2)];
                       if(m==1)    primes[0] = 1;
                        for(i=2; i<=Math.sqrt(n); i++)
                        {
                            j = (m/i);    j *= i;
                            if(j<m)
                                j+=i;
                            for(; j<=n; j+=i)
                             {
                                 if(j!=i)
                                    primes[(int)(j-m)] = 1;
                             }
                        }

                for(i=0; i<=n-m; i++)
                            if(primes[(int)i]==0 && (i-1)%k==0)
                                count++;
                return count;
                }
}
class SegTree {
    int n;
    long  t[];
    long mod=(long)(1000000007);
    SegTree(int n,long  t[]){
        this.n=n;
        this.t=t;
        //build();
    }
    
    void build() {  // build the tree
        
        for (int i = n - 1; i > 0; --i)
            t[i]=(t[i<<1]+t[i<<1|1]);
    }

     void modify(int p, long value) {  // set value at position p
      for (t[p += n]=value; p > 1; p >>= 1) t[p>>1] = (t[p] + t[p^1]);
    }

     long query(int l, int r) {  // sum on interval [l, r)
      long res=0;
              
      for (l += n, r += n; l < r; l >>= 1, r >>= 1) {
            if ((l&1)!=0) res=(res+t[l++]);
            if ((r&1)!=0) res=(res+t[--r]);
          }
      return res;
    }

    
    //  
//  
//  
}
class FastScanner
{

    private InputStream stream;
    private byte[] buf = new byte[8192];
    private int curChar;
    private int snumChars;
    private SpaceCharFilter filter;

    public FastScanner(InputStream stream) {
        this.stream = stream;
    }
    
    public int snext() {
        if (snumChars == -1)
            throw new InputMismatchException();
        if (curChar >= snumChars) {
            curChar = 0;
            try {
                snumChars = stream.read(buf);
            } catch (IOException e) {
                throw new InputMismatchException();
            }
            if (snumChars <= 0)
                return -1;
        }
        return buf[curChar++];
    }
    public int nextInt() {
        int c = snext();
        while (isSpaceChar(c))
            c = snext();
        int sgn = 1;
        if (c == '-') {
            sgn = -1;
            c = snext();
        }

        int res = 0;

        do {
            if (c < '0' || c > '9')
                throw new InputMismatchException();
            res *= 10;
            res += c - '0';
            c = snext();
        } while (!isSpaceChar(c));

        return res * sgn;
    }
    
    public long nextLong() {
        int c = snext();
        while (isSpaceChar(c))
            c = snext();
        int sgn = 1;
        if (c == '-') {
            sgn = -1;
            c = snext();
        }

        long res = 0;

        do {
            if (c < '0' || c > '9')
                throw new InputMismatchException();
            res *= 10;
            res += c - '0';
            c = snext();
        } while (!isSpaceChar(c));

        return res * sgn;
    }
    
    public String readString() {
        int c = snext();
        while (isSpaceChar(c))
            c = snext();
        StringBuilder res = new StringBuilder();
        do {
            res.appendCodePoint(c);
            c = snext();
        } while (!isSpaceChar(c));
        return res.toString();
    }

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

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

    private int[] parent;  // parent[i] = parent of i
    private byte[] rank;   // rank[i] = rank of subtree rooted at i (never more than 31)
    private int count;     // number of components
    public UF(int N) {
        if (N < 0) throw new IllegalArgumentException();
        count = N;
        parent = new int[N];
        rank = new byte[N];
        for (int i = 0; i < N; i++) {
            parent[i] = i;
            rank[i] = 0;
        }
    }

    public int find(int p) {
        if (p < 0 || p >= parent.length) throw new IndexOutOfBoundsException();
        while (p != parent[p]) {
            parent[p] = parent[parent[p]];    // path compression by halving
            p = parent[p];
        }
        return p;
    }
    public int count() {
        return count;
    }

    public boolean connected(int p, int q) {
        return find(p) == find(q);
    }

    public boolean union(int p, int q) {
        int rootP = find(p);
        int rootQ = find(q);
        if (rootP == rootQ) return false;

        // make root of smaller rank point to root of larger rank
        if      (rank[rootP] < rank[rootQ]) parent[rootP] = rootQ;
        else if (rank[rootP] > rank[rootQ]) parent[rootQ] = rootP;
        else {
            parent[rootQ] = rootP;
            rank[rootP]++;
        }
        count--;
        return true;
    }

}
