package no211;

import java.util.Scanner;

public class Main {
	public static int[] d1 = {2,3,5,7,11,13};
	public static int[] d2 = {4,6,8,9,10,12};
	public static void main(String[] args) {
		Scanner sc = new Scanner(System.in);
		int k = sc.nextInt();
		int count = 0;
		for(int i=0;i<6;i++) {
			for(int j=0;j<6;j++) {
				if (d1[i] * d2[j] == k) {
					count++;
				}
			}
		}
		System.out.println(count / 36D);
	}

}