#include <iostream>
#include <algorithm>

using namespace std;
const int maxn=1010;
int n,a[maxn],maxu,prosli;

int main (void){
    cin >> n;
    for (int i=0;i<n;i++){
            cin >> a[i];
            if (i==0){
                    prosli=a[i];
            }
            if (a[i]<=a[i-1]){
                    maxu=max(maxu,a[i-1]-prosli);
                    prosli=a[i];
            }
    }
    maxu=max(maxu,a[n-1]-prosli);
    cout << maxu << endl;
    return 0;
}