#include <bits/stdc++.h>
using namespace std;
int main() {
  ios_base::sync_with_stdio(0);
  int n, arr[200];
  while (cin >> n) {
    int ans = 0, arr1[200];
    for (int i = 0; i < n; i++) cin >> arr[i];
    sort(arr, arr + n);
    for (int i = 0; i < n; i++) {
      bool flag = 0;
      for (int j = 0; j < ans; j++) {
        if (arr1[j] <= arr[i]) {
          arr1[j]++;
          flag = 1;
          break;
        }
      }
      if (!flag) {
        arr1[ans++] = 1;
      }
    }
    cout << ans << endl;
  }
}
