#include <bits/stdc++.h>
using namespace std;


int main(){
    int k , max1 = -1;
    cin >> k;
    int a[k+1];
    for (int i = 1 ; i <= k ; i++){
        cin >> a[i];
    }
    sort(a+1,a+k);
    for (int i = k ; i >= 2 ; i--){
        if (a[i] - a[i-1] > max1)
            max1 = a[i] - a[i-1];
    }
    cout << max1;
    return 0;
}