LeetCode -- Minimum Number of Arrows to Burst Balloons

public class Solution {    public int FindMinArrowShots(int[,] points)     {        if(points == null){            return 0;        }        var len = points.GetLength(0);    	if(len == 0){    	    return 0;    	}    	    	var balls = new List<Balloon>(len);    	for (var i = 0;i < len; i++){    		balls.Add(new Balloon(points[i,0], points[i,1]));    	}    	    	balls = balls.OrderBy(x=>x.X1).ThenBy(x=>x.X2).ToList();    	//Console.WriteLine(balls);    	var bulletCount = 1;    	var selection = balls.First();    	var bulletX = selection.X2;    	for (var i = 1;i < balls.Count; i++){    		if(balls[i].X1 <= bulletX){    			bulletX = Math.Min(bulletX, balls[i].X2);    		}else{    			bulletX = balls[i].X2;    			bulletCount++;    		}    	}    	    	//Console.WriteLine(balls);    	    	    	return bulletCount;    }        public class Balloon{    	public int X1;    	public int X2;    	public Balloon(int x1, int x2){    		X1 = x1;    		X2 = x2;    	}    }}