In a kindergarten, the children are being divided into groups. The teacher put the children in a line and associated each child with his or her integer charisma value. Each child should go to exactly one group. Each group should be a nonempty segment of consecutive children of a line. A group's sociability is the maximum difference of charisma of two children in the group (in particular, if the group consists of one child, its sociability equals a zero). 

The teacher wants to divide the children into some number of groups in such way that the total sociability of the groups is maximum. Help him find this value.

Input

The first line contains integer n — the number of children in the line (1 ≤ n ≤ 106).

The second line contains n integers ai — the charisma of the i-th child ( - 109 ≤ ai ≤ 109).

Output

Print the maximum possible total sociability of all groups.

Examples

Input

5
1 2 3 1 2


Output

3


Input

3
3 3 3


Output

0

Note

In the first test sample one of the possible variants of an division is following: the first three children form a group with sociability 2, and the two remaining children form a group with sociability 1.

In the second test sample any division leads to the same result, the sociability will be equal to 0 in each group.

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.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;
    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 Kandy{
    long value;
    int length;
    Kandy(long value,int length){
        this.value=value;
        this.length=length;
    }
    public Kandy() {
        // TODO Auto-generated constructor stub
    }
}
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 line{
    int slope;
    int c;
    line(int slope,int c){
        this.slope=slope;;
        this.c=c;
    }
}
class TaskC {
    static long mod=1000000007;
      SegTree tree;
        int min[];
    //static int prime_len=10000;
    //static int prime[]=new int[prime_len];
    
    /*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;
            }
        }
    //  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;
            }
        
     * */
        long[] A = new long[1000000];
        long[] B = new long[1000000];
        int len;
        int ptr;

        // a descends
        public void addLine(long a, long b) {
          // intersection of (A[len-2],B[len-2]) with (A[len-1],B[len-1]) must lie to the left of intersection of (A[len-1],B[len-1]) with (a,b)
          while (len >= 2 && (B[len - 2] - B[len - 1]) * (a - A[len - 1]) >= (B[len - 1] - b) * (A[len - 1] - A[len - 2])) {
            --len;
          }
          A[len] = a;
          B[len] = b;
          ++len;
        }

        // x ascends
        public long minValue(long x) {
          ptr = Math.min(ptr, len - 1);
          while (ptr + 1 < len && A[ptr + 1] * x + B[ptr + 1] <= A[ptr] * x + B[ptr]) {
            ++ptr;
          }
          return A[ptr] * x + B[ptr];
        }
        public void solve(int testNumber, FastScanner in, PrintWriter out) throws IOException {
            int n=in.nextInt();
            long a[]=new long[n+1];
            for(int i=1;i<=n;i++){
                a[i]=in.nextLong();
            }
            if(n==1){
                out.println(0);
                return;
            }
            
            long dp[]=new long[n+1];
            for(int i=1;i<n;i++){
                if (a[i+1]>=a[i])
                  {
                     if ((i==1)||(a[i]>=a[i-1])) {
                         
                         dp[i]=dp[i-1]+a[i+1]-a[i]; 
                     }
                     else{
                    
                         dp[i]=Math.max(dp[i-1],dp[i-2]+a[i+1]-a[i]);
                         
                     }
                  }
                  else
                  {
                     if ((i==1)||(a[i]<a[i-1])) {
                         dp[i]=dp[i-1]-a[i+1]+a[i]; 
                     }
                     else{
                         dp[i]=Math.max(dp[i-1],dp[i-2]-a[i+1]+a[i]);
                         
                     }
                  }     
            }
            out.println(dp[n-1]);
        }
            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[];
    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]=Math.max(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] = Math.max(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=Math.max(res,t[l++]);
            if ((r&1)!=0) res=Math.max(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;
    }

}
