#include <bits/stdc++.h>
using namespace std;
int n, a[128];
int check(int k) {
  int cnt;
  for (int i = 0;; i += 1) {
    for (int j = 0; j < k; j += 1) {
      cnt = k * i + j;
      if (cnt == n) return 1;
      if (a[cnt] < i) return 0;
    }
  }
}
int main(int argc, char const* argv[]) {
  cin >> n;
  for (int i = 0; i < n; i += 1) {
    cin >> a[i];
  }
  sort(a, a + n);
  for (int i = 1;; i += 1) {
    if (check(i)) {
      cout << i << '\n';
      return 0;
    }
  }
  return 0;
}
