#include <bits/stdc++.h>
#pragma GCC optimize("O3")
using namespace std;
int n, v[102];
bool tk[102];
int main() {
  ios_base::sync_with_stdio(false);
  cin.tie(NULL);
  cout.tie(NULL);
  mt19937 rng(chrono::steady_clock::now().time_since_epoch().count());
  cin >> n;
  for (int i = 1; i <= n; ++i) cin >> v[i];
  sort(v + 1, v + n + 1);
  int sol = 0;
  for (int i = 1; i <= n; ++i) {
    int nr = 0;
    if (!tk[i]) {
      ++sol;
      tk[i] = 1;
      ++nr;
      for (int j = i + 1; j <= n; ++j) {
        if (tk[j]) continue;
        if (v[j] >= nr) ++nr, tk[j] = 1;
      }
    }
  }
  cout << sol;
  return 0;
}
