#include <bits/stdc++.h>
using namespace std;
const long long int inf = 1e18;
signed main() {
  ios_base::sync_with_stdio(false);
  cin.tie(NULL), cout.tie(NULL);
  vector<long long int> arr[100];
  long long int n, t, i, p, j, cnt = 0;
  cin >> n;
  long long int v[n];
  for (i = 0; i < n; i++) cin >> v[i];
  sort(v, v + n);
  for (i = 0; i < n; i++) {
    p = v[i];
    for (j = 0; j < 100; j++) {
      if (arr[j].size() <= p) {
        arr[j].push_back(p);
        cnt = max(cnt, j);
        break;
      }
    }
  }
  cout << cnt + 1 << endl;
}
