#include <iostream>

using namespace std;
int n;

int main(){
    cin >> n;
    int cnt,res = -2e9;
    for(int i = 0;i < n;i++){
        int x;
        cin >> x;
        if(i) res = max(res,abs(cnt - x));
        cnt = x;
    }
    cout << res << endl;
    return 0;
}