#include <bits/stdc++.h>
using namespace std;
int n, a[200];
int dp[200];
int main() {
  cin >> n;
  for (int i = 0; i < n; i++) cin >> a[i];
  sort(a, a + n);
  dp[0] = 1;
  for (int i = 1; i < n; i++) {
    int ma = -1, v = -1;
    for (int j = 0; j < i; j++)
      if (dp[j] <= a[i] && dp[j] > ma) ma = dp[j], v = j;
    if (ma == -1)
      dp[i] = 1;
    else {
      dp[v]++;
      dp[i] = 0;
    }
  }
  int ans = 0;
  for (int i = 0; i < n; i++)
    if (dp[i] > 0) ans++;
  cout << ans;
  return 0;
}
