using System;
using System.Collections.Generic;
using System.Linq;

namespace Test
{
    class Program
    {
        static void Main(string[] args)
        {
            int n = int.Parse(Console.ReadLine());
            int[] a = new int[] { 2,3,5,7,11,13 };
            int[] b = new int[] { 4,6,8,9,10,12 };
            double ret = 0;
            for (int i = 0; i < 6; i++)
            {
                for (int j = 0; j < 6; j++)
                {
                    if (a[i] * b[j] == n) ret++;
                }
            }
            Console.WriteLine(ret / 36);
        }
    }
}