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