#include <bits/stdc++.h>
using namespace std;
int cnt[3010 + 1];
const int mod = 1e9 + 7;
long long int inf = 100000000000000000;
bool ck[110];
vector<int> v[3010];
void solve() {
  int n;
  cin >> n;
  int a[n];
  for (int i = 0; i < n; i++) cin >> a[i];
  sort(a, a + n);
  int l = 0;
  int ans = 0;
  int j = 0;
  while (j < n) {
    l = 0;
    for (int i = 0; i < n; i++) {
      if (a[i] >= l && ck[i] == false) {
        ck[i] = true;
        l++;
        j++;
      }
    }
    ans++;
  }
  cout << ans << endl;
}
int main() {
  ios_base::sync_with_stdio(0);
  cin.tie(0);
  cout.tie(0);
  ;
  int t;
  t = 1;
  while (t--) solve();
  return 0;
}
