#include <bits/stdc++.h>
using namespace std;
int main() {
  ios_base::sync_with_stdio(0);
  cin.tie(0);
  cout.tie(0);
  int n;
  cin >> n;
  vector<int> a(n);
  for (int i = 0; i < n; ++i) cin >> a[i];
  sort(a.begin(), a.end());
  vector<int> v;
  for (int i = 0; i < n; ++i) {
    int val = a[i], idx = -1;
    for (int j = 0; j < (int)v.size(); ++j) {
      if (val >= v[j]) {
        idx = j;
        v[j]++;
        break;
      }
    }
    if (idx == -1) v.push_back(1);
  }
  cout << v.size() << "\n";
  return 0;
}
