import java.util.*;

public class Main {
    public static void main(String[] args) {
        Scanner sc = new Scanner(System.in);
        int K = sc.nextInt();
        int [] a = {2,3,5,7,11,13};
        int [] b = {4,6,8,9,10,12};
        int count = 0;
        for(int i=0; i<6; i++){
            if(K%a[i]==0){
                for(int j=0; j<6; j++){
                    if(K/a[i]==b[j]){
                        count++;
                    }
                }
            }
        }
        double r = count/36.0;
        System.out.printf("%.12f",r);
    }
}