#include <bits/stdc++.h>
using namespace std;
int box[101];
const int inf = 1e9;
int main() {
  int n;
  cin >> n;
  for (int i = 0; i <= n - 1; ++i) {
    int b;
    cin >> b;
    box[b]++;
  }
  for (int p = 1; p <= n; ++p) {
    int allowed[p];
    for (int i = 0; i <= p - 1; ++i) allowed[i] = inf;
    int c = 0;
    bool failed = 0;
    for (int i = 100; i >= 0; --i) {
      for (int j = 1; j <= box[i]; ++j) {
        if (allowed[c] > 0) {
          allowed[c] = min(allowed[c] - 1, i);
          c = (c + 1) % p;
        } else {
          failed = 1;
        }
      }
    }
    if (!failed) {
      cout << p << "\n";
      break;
    }
  }
}
