#include <bits/stdc++.h>
#pragma GCC optimize("O2")
using namespace std;
const long long MAX = 1e5 + 5;
const long long MAX2 = 11;
const int MOD = 1000000000 + 7;
const long long INF = 20000;
const int nr[] = {1, 0, -1, 0, 1, 1, -1, -1};
const int nc[] = {0, 1, 0, -1, 1, -1, 1, -1};
int n, x[MAX], y, mn, id;
vector<int> v[105];
bool st;
int main() {
  cout << fixed << setprecision(10);
  ios_base::sync_with_stdio(false);
  cin.tie(0);
  cout.tie(0);
  cin >> n;
  for (int i = 1; i <= n; i++) cin >> x[i];
  sort(x + 1, x + 1 + n);
  v[1].push_back(x[1]);
  id = 1;
  for (int i = 2; i <= n; i++) {
    st = 1;
    for (int j = 1; j <= id; j++) {
      if (v[j].size() <= x[i]) {
        v[j].push_back(x[i]);
        st = 0;
        break;
      }
    }
    if (st) v[++id].push_back(x[i]);
  }
  cout << id;
  return 0;
}
