#include <bits/stdc++.h>
using namespace std;
bool possible(int x[], int n, int k) {
  for (int i = 0; i < n; ++i) {
    if (x[i] < i / k) {
      return false;
    }
  }
  return true;
}
int main(int argc, char* argv[]) {
  int n;
  int x[101];
  cin >> n;
  for (int i = 0; i < n; ++i) {
    cin >> x[i];
  }
  sort(x, x + n);
  int s = 1;
  int e = n;
  int ans;
  for (int k = 1; k <= n; ++k) {
    if (possible(x, n, k)) {
      cout << k << endl;
      return 0;
    }
  }
  return 0;
}
