#include <bits/stdc++.h>
using namespace std;
int main() {
  cin.sync_with_stdio(false);
  int n;
  cin >> n;
  vector<int> v(n);
  for (int i = 0; i < n; i++) {
    cin >> v[i];
  }
  vector<int> sol(101);
  for (int i = 0; i < n; i++) {
    sol[v[i]]++;
  }
  int blocks[101];
  int spaces[101];
  blocks[0] = sol[0];
  spaces[0] = 0;
  for (int i = 1; i < 101; i++) {
    int k = sol[i];
    spaces[i - 1] = spaces[i - 1] + blocks[i - 1];
    if (k <= spaces[i - 1]) {
      spaces[i] = spaces[i - 1] - k;
      blocks[i] = blocks[i - 1];
    } else {
      k = k - spaces[i - 1];
      int b = k / (i + 1);
      if (k % (i + 1) == 0) {
        blocks[i] = blocks[i - 1] + b;
        spaces[i] = 0;
      } else {
        blocks[i] = blocks[i - 1] + b + 1;
        spaces[i] = i + 1 - k % (i + 1);
      }
    }
  }
  cout << blocks[100];
}
