#include <bits/stdc++.h>
using namespace std;
int main() {
  int n, in, pile = 0;
  cin >> n;
  int max_st = -1;
  int box[101] = {0};
  for (long long i = 1; i <= n; i++) {
    cin >> in;
    if (in > max_st) max_st = in;
    box[in] += 1;
  }
  int box_left = n;
  int pile_h = 0;
  while (1) {
    pile_h = 0;
    if (box_left == 0) break;
    int j;
    for (j = 0; j <= max_st;) {
      if (box[j] > 0) {
        pile_h = pile_h + 1;
        box[j] = box[j] - 1;
        box_left = box_left - 1;
        ;
        j = pile_h;
      } else
        j++;
    }
    pile = pile + 1;
  }
  cout << pile;
}
