using System;

public class Hello
{
    public static void Main()
    {
        var a = new int[] { 2, 3, 5, 7, 11, 13 };
        var b = new int[] { 4, 6, 8, 9, 10, 12 };
        var ans = 0d;
        var k = int.Parse(Console.ReadLine().Trim());
        foreach (var x in a)
            foreach (var y in b)
                if (x * y == k) ans += 1 / 36d;
        Console.WriteLine(ans);
    }
}