#include <bits/stdc++.h>
using namespace std;
int main(int argc, char** argv) {
  int N;
  cin >> N;
  vector<int> vec(N);
  for (int i = 0; i < N; i++) cin >> vec[i];
  sort(vec.begin(), vec.end());
  vector<int> H;
  vector<int> L;
  L.push_back(vec[0]);
  H.push_back(1);
  for (int i = 1; i < N; i++) {
    int curr = vec[i];
    for (int j = 0; j < H.size(); j++) {
      if (H[j] <= curr) {
        H[j]++;
        L[j] = curr;
        break;
      }
      if (j == H.size() - 1) {
        H.push_back(1);
        L.push_back(curr);
        break;
      }
    }
  }
  cout << H.size();
  return 0;
}
