#include <bits/stdc++.h>
using namespace std;
int main(void) {
  int n;
  cin >> n;
  int arr[n];
  for (int i = 0; i < n; i++) {
    cin >> arr[i];
  }
  sort(arr, arr + n);
  int ans = 1;
  int height;
  for (int i = 1; i < n; i++) {
    height = i / ans;
    while (arr[i] < height) ans++, height = i / ans;
  }
  cout << ans << endl;
  return 0;
}
