#include <bits/stdc++.h>

using namespace std;
int n, x, y, res;
/*
8
151 120 144 182 160 158 147 161
*/
int main() {
    cin >> n;
    for (int i = 1; i <= n; i++) {
        cin >> y;
        if (x) res = max(res, abs(y - x));
        x = y;
    }
    cout << res << endl;
    return 0;
}