#include <bits/stdc++.h>
using namespace std;
int n;
int x[1000001];
bool check(int piles) {
  for (int i = 0; i < n; i++) {
    if (x[i] < i / piles) return false;
  }
  return true;
}
int main() {
  cin >> n;
  for (int i = 0; i < n; i++) cin >> x[i];
  sort(x, x + n);
  int L = 0, R = n, M;
  while (R - L > 1) {
    M = (L + R) / 2;
    if (check(M))
      R = M;
    else
      L = M;
  }
  cout << R << endl;
  return 0;
}
