using System;

public class Program

{

        static private double avg(double a1, double a2 , double a3 , double a4)

    {

        double avgadd = a1+a2+a3+a4;

        double av = avgadd / 4; 

            return av; 

    }

    public static void Main()

    {

        Console.WriteLine("what is your first number .");

        double avg1 = double.Parse(Console.ReadLine());

        Console.WriteLine("what is your second number .");

        double avg2 = double.Parse(Console.ReadLine());

        Console.WriteLine("what is your third number .");

        double avg3 = double.Parse(Console.ReadLine());

        Console.WriteLine("what is your fourth number .");

        double avg4= double.Parse(Console.ReadLine());

        double output = avg(avg1, avg2,avg3,avg4);

        Console.WriteLine("The average of your four number is  " + output.ToString("##.###"));

    }

}