#include <bits/stdc++.h>
using namespace std;
int main() {
  int n;
  cin >> n;
  int a[n];
  for (int i = 0; i < n; i++) cin >> a[i];
  int ans = 0;
  ans = a[0];
  int energy = 0;
  for (int i = 0; i < n - 1; i++) {
    if (a[i] >= a[i + 1]) {
      energy += a[i] - a[i + 1];
    } else {
      if ((a[i] + energy) >= a[i + 1]) {
        energy = energy - (a[i + 1] - a[i]);
      } else {
        ans += a[i + 1] - energy - a[i];
        energy = 0;
      }
    }
  }
  cout << ans << endl;
  return 0;
}
