#include <bits/stdc++.h>
using namespace std;
int n, a[105];
bool ok(int k) {
  for (int i = 1; i <= n; ++i)
    if ((i - 1) / k > a[i]) return false;
  return true;
}
int main() {
  cin >> n;
  for (int i = 1; i <= n; ++i) cin >> a[i];
  sort(a + 1, a + n + 1);
  for (int i = 1; i <= n; ++i)
    if (ok(i)) {
      cout << i << '\n';
      break;
    }
  return 0;
}
