#include <bits/stdc++.h>
using namespace std;
template <typename T>
T modpow(T base, T exp, T modulus) {
  base %= modulus;
  T result = 1;
  while (exp > 0) {
    if (exp & 1) result = (result * base) % modulus;
    base = (base * base) % modulus;
    exp >>= 1;
  }
  return result;
}
struct cmp {
  bool operator()(const pair<int, int> &a, const pair<int, int> &b) const {
    int lena = a.second - a.first + 1;
    int lenb = b.second - b.first + 1;
    if (lena == lenb) return a.first < b.first;
    return lena > lenb;
  }
};
long long calcpow(long long x, long long y) {
  long long temp;
  if (y == 0) return 1;
  temp = calcpow(x, y / 2);
  if (y % 2 == 0)
    return temp * temp;
  else {
    if (y > 0)
      return x * temp * temp;
    else
      return (temp * temp) / x;
  }
}
long long gcd(long long a, long long b) {
  if (b == 0) return a;
  return gcd(b, a % b);
}
long long egcd(long long a, long long b, long long &x, long long &y) {
  if (b == 0) {
    x = 1;
    y = 0;
    return a;
  }
  long long x1;
  long long y1;
  long long g = egcd(b, a % b, x1, y1);
  x = y1;
  y = x1 - y1 * (a / b);
  return g;
}
bool isprime(long long a) {
  bool flag = 1;
  for (long long i = 2; i * i <= a; i++) {
    if (a % i == 0) {
      flag = 0;
      break;
    }
  }
  return flag;
}
int main() {
  ios_base::sync_with_stdio(false);
  cin.tie(NULL);
  long long n;
  cin >> n;
  vector<long long> vec(n);
  for (long long i = 0; i < n; i++) cin >> vec[i];
  sort(vec.begin(), vec.end());
  long long c = 0;
  long long prev = 0;
  vector<long long> vis(n, 0);
  long long p = 0;
  while (p < n) {
    long long prev = 0;
    for (long long i = 0; i < n; i++) {
      if (vis[i] == 0 && vec[i] >= prev) {
        vis[i] = 1;
        p++;
        prev++;
      }
    }
    c++;
  }
  cout << c << endl;
  return 0;
}
