#include <bits/stdc++.h>
using namespace std;
int getIndexFromVector(vector<int>& v, int num) {
  for (int i = 0; i < v.size(); i++) {
    if (v[i] <= num) return i;
  }
  return -1;
}
int main() {
  std::ios::sync_with_stdio(false);
  cin.tie(NULL);
  int n;
  cin >> n;
  int arr[n];
  for (int i = 0; i < n; i++) cin >> arr[i];
  sort(arr, arr + n);
  vector<int> v;
  for (int i = 0; i < n; i++) {
    int index = getIndexFromVector(v, arr[i]);
    if (index == -1) {
      v.push_back(1);
    } else {
      v[index] += 1;
    }
  }
  cout << v.size() << endl;
}
