#include <bits/stdc++.h>
using namespace std;
int main() {
  long long n;
  cin >> n;
  vector<pair<long long, pair<long long, long long> > > v;
  for (long long i = 1; i <= n; i++) {
    long long x;
    cin >> x;
    v.push_back(make_pair(x, make_pair(1, x)));
  }
  sort(v.begin(), v.end());
  while (1) {
    bool paisi = true;
    for (long long i = 0; i < v.size() - 1; i++) {
      if (v[i].first == -1) continue;
      int keep = v[i].second.first;
      for (long long j = i + 1; j < v.size(); j++) {
        int temp = v[j].second.second;
        if (keep <= temp) {
          v[j].second.first += v[i].second.first;
          v[j].second.second =
              min(v[i].second.second, (v[j].second.second) - keep);
          paisi = false;
          v[i].first = -1;
          break;
        }
      }
    }
    if (paisi) {
      int cnt = 0;
      for (long long i = 0; i < v.size(); i++) {
        if (v[i].first != -1) cnt++;
      }
      printf("%d\n", cnt);
      return 0;
    }
  }
  return 0;
}
