using System;

​

public class Foo

{

    public static string operator +(Foo left, Bar right)

    {

        return "Foo is on the left";

    }

}

​

public class Bar

{

    public static string operator +(Bar left, Foo right)

    {

        return "Bar is on the left";

    }

}

​

public class Program

{

    public static void Main()

    {

        Console.WriteLine(new Foo() + new Bar());

        Console.WriteLine(new Bar() + new Foo());

    }

}