#include <bits/stdc++.h>
using namespace std;
int main() {
  int n, a[105], j, i, count = 0, res = 1, idx = 0;
  cin >> n;
  int b[105] = {0};
  for (i = 0; i < n; i++) cin >> a[i];
  sort(a, a + n);
  for (i = 1; i < n; i++) {
    if (i / res > a[i]) res++;
  }
  cout << res << endl;
  return 0;
}
