using System;

class d

{

    public string Value;

    public static d operator +(d a,d b)

    {

        a.Value += b.Value;

        return a;

    }

}

​

class f<T>

{

    public d Plus(d par1,d par2)

    {

        return par1+par2;

    }

}

    public class Program

{

    public static void Main()

    {

        f<d> x=new f<d>();

    d r=new d();

        r.Value="vai";

    d r1=new d();

        r1.Value="ha";

    d o=x.Plus(r,r1);

        Console.WriteLine(o.Value.ToString());

    }

}