#include <bits/stdc++.h>
using namespace std;
int arr[2000], cap[2000];
int main() {
  int a, b, c, i, j, k, n, m;
  while (scanf("%d", &n) != EOF) {
    for (i = 0; i < n; i++) scanf("%d", &arr[i]);
    sort(arr, arr + n);
    for (i = 0; i < n; i++) cap[i] = 0;
    m = 0;
    for (i = 0; i < n; i++) {
      for (j = 0; j < m; j++) {
        if (cap[j] <= arr[i]) {
          cap[j]++;
          break;
        }
      }
      if (j == m) {
        cap[m] = 1;
        m++;
      }
    }
    printf("%d\n", m);
  }
  return 0;
}
