#include <bits/stdc++.h>
using namespace std;
void nl() { printf("\n"); }
void sc(int& n) {
  int number;
  scanf("%d", &number);
  n = number;
}
void sc(long long& n) {
  long long number;
  scanf("%lld", &number);
  n = number;
}
void _print(long long t) { printf("%lld ", t); }
void _print(int t) { printf("%d ", t); }
void _print(string t) { cout << t; }
void _print(char t) { printf("%c\n", t); }
void _print(long double t) { cout << t; }
void _print(double t) { cout << t; }
void _print(unsigned long long t) { cout << t; }
template <class T, class V>
void _print(pair<T, V> p);
template <class T>
void _print(vector<T> v);
template <class T>
void _print(set<T> v);
template <class T, class V>
void _print(map<T, V> v);
template <class T>
void _print(multiset<T> v);
template <class T, class V>
void _print(pair<T, V> p) {
  cout << "{";
  _print(p.first);
  cout << ",";
  _print(p.second);
  cout << "}";
}
template <class T>
void _print(vector<T> v) {
  cout << "vec->[ ";
  for (T i : v) {
    _print(i);
    cout << " ";
  }
  cout << "]";
}
template <class T>
void _print(set<T> v) {
  cout << "set->[ ";
  for (T i : v) {
    _print(i);
    cout << " ";
  }
  cout << "]";
}
template <class T>
void _print(multiset<T> v) {
  cout << "multiset->[ ";
  for (T i : v) {
    _print(i);
    cout << " ";
  }
  cout << "]";
}
template <class T, class V>
void _print(map<T, V> v) {
  cout << "map->[ ";
  for (auto i : v) {
    _print(i);
    cout << " ";
  }
  cout << "]";
}
const long long inf = (long long)1e15 + 10;
const int N = (int)1e6 + 10;
int x[109];
void solve() {
  int n;
  cin >> n;
  std::vector<int> v;
  for (int i = 0; i < n; i++) {
    int t;
    cin >> t;
    x[t]++;
  }
  for (int i = 0; i <= 100; i++) {
    int u = 0;
    while (x[i] > 0) {
      if (u < v.size()) {
        v[u]++;
        if (v[u] > i) u++;
      } else {
        v.push_back(1);
        if (v[u] > i) u++;
      }
      x[i]--;
    }
  }
  cout << (v.size());
}
int main() {
  int t = 1;
  while (t--) {
    solve();
  }
  return 0;
}
