#include <bits/stdc++.h>
using namespace std;
int a[102], n;
bool valid(int group) {
  int mn[102] = {0};
  for (int i = 0; i < n; ++i) {
    if (mn[i % group] > a[i]) return 0;
    mn[i % group]++;
  }
  return 1;
}
int main() {
  cin >> n;
  for (int i = 0; i < n; ++i) scanf("%d", a + i);
  sort(a, a + n);
  for (int i = 1; i <= n; ++i) {
    if (valid(i)) {
      cout << i;
      return 0;
    }
  }
}
