using System;

​

public class Numbers

{

    public int  Sum(int a , int b) { return a + b; }

    public string Sum(string a, string b)

    { 

        return a+b;

​

    }

​

​

}

​

namespace ConsoleApp1

{

    class Program

    {

        static void Main(string[] args)

        {

            Numbers n = new Numbers();

            Console.WriteLine(   n.Sum(5, 4));

            Console.WriteLine(n.Sum("ha","ha"));

​

        }

    }

}