#include <bits/stdc++.h>
using namespace std;
long long gcd(long long x, long long y) {
  if (y == 0)
    return x;
  else
    return gcd(y, x % y);
}
long long expo(long long n, long long m) {
  long long r = 1;
  while (m > 0) {
    if (m % 2) r = (r * n) % 1000000007;
    n = (n * n) % 1000000007;
    m = m / 2;
  }
  return r % 1000000007;
}
int main() {
  ios::sync_with_stdio(0);
  cin.tie(0);
  cout.tie(0);
  ;
  long long n;
  cin >> n;
  vector<long long> a(n);
  for (int i = 0; i < n; i++) cin >> a[i];
  sort(a.begin(), a.end());
  for (long long i = 1; i <= 150; i++) {
    long long c = i;
    for (long long j = n - 1; j >= n - i; j--) {
      long long k = j - i, cap = a[j];
      while (k >= 0 && cap > 0) {
        c++;
        cap = min(a[k], cap - 1);
        k -= i;
      }
    }
    if (c == n) {
      cout << i;
      return 0;
    }
  }
  return 0;
}
