#include <bits/stdc++.h>
using namespace std;
int main() {
  int N;
  cin >> N;
  int A[N];
  int s = 0;
  for (int i = 0; i < N; i++) {
    cin >> A[i];
    if (A[i] < A[i + 1]) {
      s = A[i + 1] - A[i];
    }
  }
  cout << s << endl;
}
