#include <iostream>

using namespace std;

int main()
{
    int n;
    cin >> n;
    int res = 0, pre = -1;
    while (n -- )
    {
        int x;
        cin >> x;
        if (pre != -1) res = max(res, abs(x - pre));
        pre = x;
    }
    cout << res << endl;
    return 0;
}