using System;

​

public class Program

{

    public static void Main()

    {

        int taxa = int.Parse(Console.ReadLine());

        double kecove = 0.6 * taxa;

        double ekip = 0.8 * kecove;

        double topka = 0.25 * ekip;

        double acc = 0.2 * topka;

        Console.WriteLine(taxa + kecove + ekip + topka + acc);

    }

}