#include <bits/stdc++.h>
using namespace std;
int len[111];
int x[111];
int main() {
  int n;
  scanf("%d", &n);
  for (int i = 0; i < n; i++) {
    scanf("%d", &x[i]);
  }
  sort(x, x + n);
  int ans = 0;
  for (int i = 0; i < n; i++) {
    bool can_put = false;
    for (int j = 1; j <= ans; j++) {
      if (len[j] <= x[i]) {
        len[j]++;
        can_put = true;
        break;
      }
    }
    if (!can_put) {
      ans++;
      len[ans] = 1;
    }
  }
  printf("%d\n", ans);
  return 0;
}
