#include <bits/stdc++.h>
using namespace std;
bool v[110];
int cnt[110];
vector<int> a;
int main() {
  int test;
  int n;
  cin >> n;
  for (int i = 0; i < n; i++) {
    int x;
    cin >> x;
    if (v[x] == false) {
      v[x] = true;
    }
    a.push_back(x);
    cnt[x]++;
  }
  int l = a.size();
  vector<int> v1;
  sort(a.begin(), a.end());
  int ans = 0;
  for (int k = 0; k < l; k++) {
    int i = a[k];
    int kk = 0;
    int x = v1.size();
    while (kk < x) {
      if (v1[kk] <= i) break;
      kk++;
    }
    if (kk < x)
      v1[kk]++;
    else
      v1.push_back(1);
  }
  cout << v1.size() << endl;
}
