#include <bits/stdc++.h>
const int inf = (int)1e9;
const int mod = 1e9 + 7;
using namespace std;
int a[111], ans = 0;
bool cmp(int x, int y) { return (x > y); }
bool u[111];
int main() {
  ios_base::sync_with_stdio(0);
  cin.tie(0);
  int n;
  cin >> n;
  for (int i = 1; i <= n; i++) {
    cin >> a[i];
  }
  sort(a + 1, a + 1 + n);
  for (int i = 1; i <= n; i++) {
    if (u[i]) continue;
    u[i] = 1;
    ans++;
    int cnt = 1;
    for (int j = i + 1; j <= n; j++) {
      if (!u[j] && a[j] >= cnt) {
        u[j] = 1;
        cnt++;
      }
    }
  }
  cout << ans;
  return 0;
}
