using System;

// see: https://stackoverflow.com/q/41892289/1016343

public class Program

{

    public static void Main()

    {   

        var result=AddTuples((1, 2),  (3, 4));

        Console.WriteLine($"Result is: {result}");

    }

​

    static (int x, int y) AddTuples((int x, int y) a,  (int x, int y) b)

    {

        return (a.x + b.x,  a.y + b.y);

    }

    static (int x, int y) AddTuples2((int x, int y) a = (0, 0),  (int x, int y) b = (0, 0))

    {

        return (a.x + b.x,  a.y + b.y);

    }

}