using System;

using System.Collections.Generic;

public class Program

{

    public static void Main()

    {

        //for the given array of points the result should be 2

        var result = new Ray().solution(new Point2D[] {

            new Point2D { x = -1, y = -2 },

            new Point2D { x = 1, y = 2 },

            new Point2D { x = 2, y = 4 },

        });

        Console.WriteLine(result);

    }

}

​

public class Ray

{

    public bool IsOnLine(Point2D endPoint1, Point2D endPoint2, Point2D checkPoint)

    {

         var result = (checkPoint.x - endPoint1.x) * (endPoint2.y - endPoint1.y) == (endPoint2.x - endPoint1.x) * (checkPoint.y - endPoint1.y)

                && Math.Sign(endPoint1.x) == Math.Sign(checkPoint.x) && Math.Sign(endPoint1.y) == Math.Sign(checkPoint.y); ;

            return result;

    }

    //do not change the method signature

    public int solution(Point2D[] A)

    {

        var sortedBeamsByLength = new List<Point2DWrapper>();

            foreach (var point in A)

            {

                sortedBeamsByLength.Add(new Point2DWrapper { Point = point });

            }

            sortedBeamsByLength.Sort((x, y) =>

            {

                if (x.Weight == 0 || x.Weight == 0)

                {

                    return 0;

                }

​

                return y.Weight.CompareTo(x.Weight);

            });

​

            for (var i = 0; i < sortedBeamsByLength.Count; i++)

            {

                if (i >= sortedBeamsByLength.Count)

                    break;

                var copy = new List<Point2DWrapper>(sortedBeamsByLength);

                for (var j = 0; j < copy.Count; j++)

                {

                    if (i == j)

                        continue;

                    var pointAsStartOfBeam = sortedBeamsByLength[i];

                    var isPointOnLine = IsOnLine(pointAsStartOfBeam.Point, new Point2D { x = 0, y = 0 }, copy[j].Point);

                    if (isPointOnLine)

                    {

                        sortedBeamsByLength.Remove(copy[j]);

                    }

​

                }

            }

​

            return sortedBeamsByLength.Count;

    }

}

​

public class Point2D

{

    public long x;

    public long y;

}

public class Point2DWrapper

{

    public Point2D Point;

    public long Weight { get { return Math.Abs(Point.x) + Math.Abs(Point.y); } }

}