#include <bits/stdc++.h>
using namespace std;
void solve() {
  long long n;
  cin >> n;
  long long a[n];
  for (long long int i = 0; i < n; i++) cin >> a[i];
  sort(a, a + n);
  vector<long long int> v;
  v.push_back(0);
  for (long long int i = 0; i < n; i++) {
    long long j = 0;
    while (1) {
      if (j == (long long)v.size()) {
        v.push_back(1);
        break;
      }
      if (v[j] <= a[i]) {
        v[j]++;
        break;
      }
      j++;
    }
  }
  cout << (long long)v.size();
}
int main() {
  ios_base::sync_with_stdio(false);
  cin.tie(0);
  cout.tie(0);
  long long TESTS = 1;
  while (TESTS--) {
    solve();
  }
  return 0;
}
