#include <bits/stdc++.h>
using namespace std;
const int N = 1e5;
int main() {
  ios_base::sync_with_stdio(false);
  cin.tie(NULL);
  cout << fixed;
  cout.precision(10);
  ;
  int n;
  cin >> n;
  vector<int> arr(n);
  for (auto &i : arr) cin >> i;
  sort(arr.begin(), arr.end());
  int temp[101]{};
  int cnt = 0;
  for (int i = 0; i < n; i++) {
    for (int j = 1; j <= 100; j++) {
      if (temp[j] <= arr[i]) {
        temp[j]++;
        break;
      }
    }
  }
  for (long long i = 1; i < 101; i++) cnt += (temp[i] != 0);
  cout << cnt;
  return 0;
}
