#include <bits/stdc++.h>
using namespace std;
bool vis[101];
int main() {
  ios_base::sync_with_stdio(false);
  cin.tie(NULL);
  int n;
  cin >> n;
  int x[n];
  for (int i = 0; i < n; i++) cin >> x[i];
  sort(x, x + n);
  memset(vis, 0, sizeof(vis));
  int ans = 0;
  for (int i = 0; i < n; i++) {
    if (!vis[i]) {
      ans++;
      int prev = 1;
      for (int j = i + 1; j < n; j++) {
        if (x[j] >= prev && !vis[j]) {
          vis[j] = true;
          prev++;
        }
      }
    }
  }
  cout << ans;
  return 0;
}
