#include <bits/stdc++.h>
using namespace std;
int main() {
  ios_base::sync_with_stdio(false);
  cin.tie(NULL);
  int n;
  cin >> n;
  int str[n];
  for (int i = 0; i < n; i++) cin >> str[i];
  sort(str, str + n);
  int piles = 1;
  for (int boxseen = 1; boxseen < n; boxseen++) {
    if (str[boxseen] < (boxseen / piles)) piles++;
  }
  cout << piles;
}
