#include <bits/stdc++.h>
using namespace std;
const int N = 10010;
int n, mx, pre, nxt;

int main() {
    cin >> n >> pre;
    for (int i = 2; i <= n; i++) {
        cin >> nxt;
        if (abs(nxt - pre) > mx) mx = abs(nxt - pre);
        pre = nxt;
    }
    cout << mx;
    return 0;
}