#include <bits/stdc++.h>
using namespace std;
int vk[105];
int i, nr, n, ax, k;
int construct() {
  int ax = 0;
  int k = 0;
  int b = 0;
  for (ax = 0; ax <= 100; ax++) {
    k++;
    while ((k > 0) && (vk[ax] > 0)) {
      k--;
      vk[ax]--;
    }
    if (vk[ax] != 0) b = 1;
  }
  return b;
}
int main(void) {
  cin >> n;
  for (i = 1; i <= n; i++) {
    cin >> nr;
    vk[nr]++;
  }
  k = 1;
  while (construct() == 1) k++;
  cout << k;
  return 0;
}
