using System;

public class Program

{

    private static readonly double epsilon = Epsilon();

​

    public static void Main(string[] args)

    {

        Console.WriteLine(epsilon);

    }

​

    public static double Epsilon()

    {

        double tau = 1.0;

        double walt = 1.0;

        double wneu = 0.0;

​

        while (wneu != walt)

        {

            tau *= 0.5;

            wneu = walt + tau;

        }

​

        return 2.0 * tau;

    }

}