using System;
using System.Linq;

namespace BingoGame_CS
{
    class Program
    {
        static void Main(string[] args)
        {
            Solver sol = new Solver();
            sol.Solve();
        }
    }
    class Solver
    {
        int N;
        const int max = 99;

        public void Solve()
        {
            double ans = 12.0 * N * (N - 1) * (N - 2) * (N - 3) * (N - 4) / ((double)max * (max - 1) * (max - 2) * (max - 3) * (max - 4));
            Console.WriteLine(ans);
        }

        public Solver()
        {
            N = ri();
        }

        static String rs() { return Console.ReadLine(); }
        static int ri() { return int.Parse(Console.ReadLine()); }
        static long rl() { return long.Parse(Console.ReadLine()); }
        static double rd() { return double.Parse(Console.ReadLine()); }
        static String[] rsa() { return Console.ReadLine().Split(' '); }
        static int[] ria() { return Console.ReadLine().Split(' ').Select(e => int.Parse(e)).ToArray(); }
        static long[] rla() { return Console.ReadLine().Split(' ').Select(e => long.Parse(e)).ToArray(); }
        static double[] rda() { return Console.ReadLine().Split(' ').Select(e => double.Parse(e)).ToArray(); }
    }
}