#include <bits/stdc++.h>
using namespace std;
int x[105], n, wtf[105], ans;
int main() {
  scanf("%d", &n);
  for (int i = 0; i < n; ++i) scanf("%d", &x[i]);
  sort(x, x + n);
  ans = 0;
  for (int i = 0; i < n; ++i) {
    bool br = false;
    for (int j = 0; j < ans; ++j)
      if (wtf[j] <= x[i]) {
        ++wtf[j];
        br = true;
        break;
      }
    if (!br) wtf[ans++] = 1;
  }
  printf("%d", ans);
}
