#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 dolars = 0, energy = 0;
  dolars = a[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] < a[i + 1]) {
      if (energy >= a[i + 1] - a[i])
        energy -= a[i + 1] - a[i];
      else {
        dolars += abs(a[i + 1] - a[i]) - energy;
        energy = 0;
      }
    }
  }
  cout << dolars;
  return 0;
}
