#include <bits/stdc++.h>
using namespace std;
long long GCDFast(long long a, long long b) {
  while (b) b ^= a ^= b ^= a %= b;
  return a;
}
int dx[8] = {-1, 0, 1, 0, -1, 1, 1, -1};
int dy[8] = {0, 1, 0, -1, 1, 1, -1, -1};
long long a[100005], b[105];
int main() {
  long long n, i, j, k, temp, m;
  long long x, y, z, sum, test_case = 0, length, ans, test = 0, l, w, num;
  string str, str1;
  i = 1;
  while (cin >> n) {
    for (i = 0; i < n; i++) cin >> a[i];
    sort(a, a + n);
    memset(b, 0, sizeof b);
    k = 1;
    for (i = 0; i < n; i++) {
      int flag = 0;
      for (j = 0; j < k; j++) {
        if (b[j] <= a[i]) {
          flag = 1;
          b[j]++;
          break;
        }
      }
      if (flag == 0) {
        b[k]++;
        k++;
      }
    }
    cout << k << "\n";
  }
  return 0;
}
