#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <stdbool.h>
int main(void)
{
    int seki,sekicnt=0;
    double chance=0;
    int sosudice[]={2,3,5,7,11,13};
    int gouseidice[]={4,6,8,9,10,12};
    scanf("%d",&seki);
    for(int i=0;i<6;i++)
    {
        for(int j=0;j<6;j++)
        {
            if(sosudice[i]*gouseidice[j]==seki)
            {
                sekicnt++;
            }
        }
    }
    chance=(double)sekicnt/36;
    printf("%.12f",chance);
}