#include <bits/stdc++.h>
using namespace std;
int main() {
  int n, x[100], height[100], ans = 0;
  cin >> n;
  for (int i = 0; i < n; i++) cin >> x[i];
  sort(x, x + n);
  for (int i = 0; i < n; i++) {
    bool find = false;
    for (int j = 0; j < ans; j++) {
      if (height[j] <= x[i]) {
        find = true;
        height[j]++;
        break;
      }
    }
    if (!find) {
      ans++;
      height[ans - 1] = 1;
    }
  }
  cout << ans;
  return 0;
}
