#include <bits/stdc++.h>
using namespace std;
int main() {
  int n, a[200000], money, energy, i;
  scanf("%d", &n);
  for (i = 0; i <= n - 1; i++) {
    scanf("%d", &a[i]);
  }
  energy = 0;
  money = a[0];
  for (i = 0; i <= n - 2; i++) {
    if (energy + a[i] - a[i + 1] < 0) {
      money += a[i + 1] - a[i] - energy;
      energy = 0;
    } else {
      energy += a[i] - a[i + 1];
    }
  }
  printf("%d\n", money);
  return 0;
}
