using System;
using System.Linq;

class Program
{
    static void Main(string[] args)
    {
        double[] sosuu = new double[] { 2, 3, 5, 7, 11, 13 };
        double[] gouseisuu = new double[] { 4, 6, 8, 9, 10, 12 };

        int K = int.Parse(Console.ReadLine());
        double d = 0;
        int match = 0;
        for (int i = 0; i < sosuu.Length; i++)
        {
            if (K % sosuu[i] > 0) { continue; }
            d = (double)K / sosuu[i];
            for (int j = 0; j < gouseisuu.Length; j++)
            {
                if (d > gouseisuu[j]) { continue; }
                if (d < gouseisuu[j]) { break; }
                if (d == gouseisuu[j]) { match++; }
            }
        }

        if (match == 0) { Console.WriteLine(0); }
        else { Console.WriteLine((double)(match / Math.Pow(6, 2))); }
    }
}