using System;

class Program
{
    static void Main()
    {
        int k = int.Parse(Console.ReadLine());

        int[] a = { 2, 3, 5, 7, 11, 13 };
        int[] b = { 4, 6, 8, 9, 10, 12 };
        double cnt = 0;

        for(int i = 0; i < 6; i++)
        {
            for (int j = 0; j < 6; j++)
            {
                if (k == a[i] * b[j]) cnt++;               
            }
        }

        Console.WriteLine(cnt / 36);
    }
}