hackerrank.com Queues A Tale of Two Stacks in; C#

hackerrank.com Queues A Tale of Two Stacks in; C#

/**
The challenge:
https://www.hackerrank.com/challenges/ctci-queue-using-two-stacks
**/

using System;
using System.Collections.Generic;
using System.IO;
class Solution {
    static void Main(String[] args) 
    {
    
            string thing = Console.ReadLine();
            //Console.WriteLine(thing);

            int q;
            Int32.TryParse(thing, out q);

            //if q too big exit.
            if(q<1 || q>100000)
            {
                System.Environment.Exit(0);
            }


            int x = 0;
            int y = 0;
            List<int> list = new List<int>();

            for (int i = 0; i < q; i++)
            {
                thing = Console.ReadLine();
                string[] commands = thing.Split(null);
                int check = commands.Length;

                if (commands != null)
                {
                    if(check == 1)
                    {
                        if (commands[0] != null)
                        {

                            Int32.TryParse(commands[0], out x);
                            //Console.WriteLine(x);


                            if (x == 2)
                            {
                                list.RemoveAt(0);

                            }
                            if (x == 3)
                            {
                                Console.WriteLine(list[0]);

                            }

                        }

                    }

                    if (check == 2)
                    {
                        if (commands[0] != null)
                        {

                            Int32.TryParse(commands[0], out x);
                            //Console.WriteLine(x);
                        }

                        if (commands[1] != null)
                        {
                            Int32.TryParse(commands[1], out y);
                            //Console.WriteLine(y);

                            if (x == 1 && y< 1000000000 && y >1)
                            {
                                list.Add(y);
                            }

                        }

                    }

                    //exit if too many arguments
                    if(check != 1 && check != 2)
                    {
                        System.Environment.Exit(0);
                    }
                    // exit if command unknown
                    if (x != 1 && x != 2 && x!= 3)
                    {
                        System.Environment.Exit(0);
                    }

                }

                //Console.WriteLine(" ");

            }
        
        /*
            Console.WriteLine("List elements:");
            foreach ( var element in list)
            {
                Console.WriteLine(element);
            }
            */
            


        /* Enter your code here. Read input from STDIN. Print output to STDOUT. Your class should be named Solution */
    }
}