#include <bits/stdc++.h>
using namespace std;
const int maxn = 110;
int A[maxn], n;
int num[maxn];
bool check(int pile) {
  memset(num, 0, sizeof(num));
  for (int i = 1; i <= n; i++) {
    int j;
    for (j = 1; j <= pile; j++)
      if (num[j] <= A[i]) {
        num[j]++;
        break;
      }
    if (j > pile) return false;
  }
  return true;
}
int main() {
  scanf("%d", &n);
  for (int i = 1; i <= n; i++) scanf("%d", &A[i]);
  sort(A + 1, A + n + 1);
  int L = 1, R = n;
  while (L <= R) {
    int M = (L + R) >> 1;
    if (check(M))
      R = M - 1;
    else
      L = M + 1;
  }
  printf("%d\n", R + 1);
  return 0;
}
