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

class Program
{     
    static void Main(string[] args)
    {
        var primes = new List<int> { 2, 3, 5, 7, 11, 13 };
        var composite = new List<int> { 4, 6, 8, 9, 10, 12 };
        var combination = new List<int>(36);

        for (int i = 0; i < primes.Count(); i++)
            for (int j = 0; j < composite.Count(); j++)
                combination.Add(primes[i] * composite[j]);

        var K = int.Parse(Console.ReadLine());
        var cnt_K = combination.Count(item => item == K);
        Console.WriteLine("{0}", ((double)cnt_K / combination.Count()));
    }
}