using System;

public class Program

{

    public static void Main()

    {

        ITest a = new Test 

            { 

                Value1 = 1,

                Value2 = 2

            };

            //Your code goes here

            Console.WriteLine(a.Sum());

    }

}

​

public interface ITest

{

    int Value1 {get;}

    int Value2 {get;}

    int Sum()

    {

        return Value1 + Value2;

    }

}

​

public class Test: ITest

{

    public int Value1 {get; set;}

    public int Value2 {get; set;}

}