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

namespace YukiCoder
{
    class Program
    {
        static void Main(string[] args)
        {
            int NN = int.Parse(Console.ReadLine());
            int nc = 0;
            foreach (int nx in new int[] { 2, 3, 5, 7, 11, 13 })
            {
                foreach (int ny in new int[] { 4, 6, 8, 9, 10, 12 })
                {
                    if (nx * ny == NN) nc++;
                }
            }
            Console.WriteLine((double)nc / 36);
            Console.ReadLine();
        }
    }
}