#include <bits/stdc++.h>
using namespace std;
int n, a[111];
vector<int> L[111];
bool ok;
int main() {
  cin >> n;
  for (int i = 0; i < n; ++i) cin >> a[i];
  sort(a, a + n);
  int cnt = 0;
  for (int i = 0; i < n; ++i) {
    ok = 1;
    for (int j = 0; j < cnt; ++j) {
      if (a[i] >= L[j].size()) {
        L[j].push_back(a[i]);
        ok = false;
        break;
      }
    }
    if (ok) L[cnt++].push_back(a[i]);
  }
  cout << cnt;
  return 0;
}
