using System;

using System.Xml.Linq;

public class Program

{

    // Don't change

    public struct MyPoint

    {

        public int X {get;set;}

        public int Y {get;set;}

        public void ChangeX(int newX) {X = newX;}

    }

    public class My

    {

        private MyPoint _point;

        public My()

        {

            _point = new MyPoint {X = 5, Y = 5};

        }

        public ref MyPoint Point => ref _point;

        public void ChangeX(int newX)

        {

            Point.ChangeX(newX);

        }

    }

    public static void Main()

    {

        var p = new MyPoint {X = 10, Y = 10};

​

        p.ChangeX(100);

        Console.WriteLine(p.X);

        var m = new My();

        m.Point.ChangeX(50);

        Console.WriteLine(m.Point.X);

        m.ChangeX(500);

        Console.WriteLine(m.Point.X);

    }

}