// 1055
#include <cstdio>
#include <algorithm>
using namespace std;
int n;
int a[100005];
long long f[100005][2];
int main()
{
    scanf("%d", &n);
    for (int i = 1; i <= n; ++i)
    {
        scanf("%d", &a[i]);
    }
    f[1][1] = -a[1];
    for (int i = 2; i <= n; ++i)
    {
        f[i][1] = max(f[i - 1][0] - a[i], f[i - 1][1]);
        f[i][0] = max(f[i - 1][0], f[i - 1][1] + a[i]);
    }
    printf("%d\n", max(f[n][0], f[n][1]));
    return 0;
}