#include <bits/stdc++.h>
using namespace std;
const int inf = 0x3f3f3f3f;
int a[102];
int n;
int cnt = 0;
int cou[101];
int main() {
  scanf("%d", &n);
  int x;
  memset(a, inf, sizeof(a));
  for (int i = 1; i <= n; i++) {
    scanf("%d", &a[i]);
  }
  sort(a + 1, a + 1 + n);
  for (int i = 1; i <= n; i++) {
    int bl = 0;
    for (int j = 1; j <= cnt; j++) {
      if (a[i] >= cou[j]) {
        cou[j]++;
        bl = 1;
        break;
      }
    }
    if (bl == 0) {
      cnt++;
      cou[cnt]++;
    }
  }
  printf("%d", cnt);
}
