#include <bits/stdc++.h>
using namespace std;
const int N = 100 + 5;
int n, res, a[N];
bool picked[N];
void Input() {
  cin >> n;
  for (int i = 1; i <= n; i++) cin >> a[i];
  sort(a + 1, a + n + 1);
}
void Solve() {
  for (int i = 1; i <= n; i++) {
    if (!picked[i]) {
      int curr_boxes = 1;
      for (int j = i + 1; j <= n; j++) {
        if (a[j] >= curr_boxes && !picked[j]) {
          curr_boxes++;
          picked[j] = true;
        }
      }
      if (curr_boxes > 0) res++;
    }
  }
  cout << res << '\n';
}
int main() {
  Input();
  Solve();
  return 0;
}
