#include <bits/stdc++.h>
using namespace std;
int n, m, a[1005], p[1005];
int main() {
  scanf("%d", &n);
  for (int i = 0; i < n; ++i) scanf("%d", a + i);
  sort(a, a + n);
  for (int i = 0; i < n; ++i) {
    int w = -1;
    for (int j = 0; j < m; ++j)
      if (p[j] <= a[i]) {
        ++p[j], w = j;
        break;
      }
    if (w < 0) p[m++] = 1, w = m;
    while (w + 1 < m && p[w] > p[w + 1]) swap(p[w], p[w + 1]);
  }
  printf("%d\n", m);
  return 0;
}
