#include <bits/stdc++.h>
using namespace std;
int box_strength[111], piles[111];
int main() {
  int num, i, j;
  cin >> num;
  for (i = 0; i <= num - 1; i++) cin >> box_strength[i];
  sort(box_strength, box_strength + num);
  int pile_index = 0, min = INT_MAX, min_index;
  for (i = 0; i <= num - 1; i++) {
    min = INT_MAX;
    if (i == 0)
      piles[pile_index++] = 1;
    else {
      if (piles[0] <= box_strength[i])
        piles[0]++;
      else
        piles[pile_index++] = 1;
    }
    for (j = 0; j <= pile_index - 1; j++)
      if (min > piles[j]) min = piles[j], min_index = j;
    swap(piles[0], piles[min_index]);
  }
  cout << pile_index << endl;
  return 0;
}
