using System;

public class Program

{

    public static void Main()

    {

        double dollars , onedollar,shekel,Shekels;

        dollars=double.Parse(Console.ReadLine());

        onedollar= 3.6;

        shekel=double.Parse(Console.ReadLine());

        Shekels=shekel*onedollar;

        Console.WriteLine(Shekels);

    }

}