package m.shin;
import java.util.Scanner;
public class Con211 {

	public static void main(String[] args) {
		Scanner s = new Scanner(System.in);
		int k = s.nextInt() , count = 0;;
		s.close();

		int[] so = {2 , 3 , 5 , 7 , 11 , 13};
		int[] go = {4 , 6 , 8 , 9 , 10 , 12};
		for(int t : so){
			for(int g : go){
				if(t * g == k){
					count++;

				}
			}
		}
		double answer = (double)count / 36;
		System.out.println(answer);

	}

}