#include<stdio.h>
#include<stdlib.h>
#include<math.h>

int max(int a,int b){
    return a < b ? b : a;
}

int main(){
    int n;
    scanf("%d",&n);
    int arr[n + 5];
    for(int i = 0; i < n; ++i){
        scanf("%d",&arr[i]);
    }
    int b1 = -arr[0],s1 = 0;
    int b2 = -arr[0],s2 = 0;

    for (int i = 1; i < n; ++i){
        b1 = max(b1, -arr[i]);
        s1 = max(s1,b1 + arr[i]);
        b2 = max(b2,s1 - arr[i]);
        s2 = max(s2,b2 + arr[i]);
    }

    printf("%d",s2);
    return 0;
}