#include <bits/stdc++.h>
using namespace std;
using namespace std::chrono;
int main() {
  auto start = high_resolution_clock::now();
  ios_base::sync_with_stdio(false);
  cin.tie(nullptr);
  int n;
  cin >> n;
  vector<int> v(n);
  for (int i = 0; i < n; ++i) cin >> v[i];
  sort(v.begin(), v.end());
  priority_queue<int, vector<int>, greater<int>> pq;
  int ans = 0;
  for (int i : v) {
    if (pq.empty()) {
      ++ans;
      pq.push(1);
    } else {
      int top = pq.top();
      if (top <= i) {
        pq.pop();
        pq.push(top + 1);
      } else {
        pq.push(1);
        ++ans;
      }
    }
  }
  cout << ans << endl;
  cerr << "Total execution time : "
       << duration_cast<milliseconds>(high_resolution_clock::now() - start)
              .count()
       << " ms" << endl;
  return 0;
}
