import java.util.*;

public class Main {
  public static void main(String[] args) {
    Scanner sc = new Scanner(System.in);
    int K = sc.nextInt();
    int[] prime = {2, 3, 5, 7, 11, 13};
    int[] compo = {4, 6, 8, 9, 10, 12};
    int a = 0;
    for(int i = 0; i < 6; i++) {
      for(int j = 0; j < 6; j++) {
        if(prime[i] * compo[j] == K) a++;
      }
    }
    double ans = (double)a / (double)36;
    System.out.println(ans);
  }
}