Array Manipulator

using System;
using System.Collections.Generic;
using System.Linq;


namespace ArrayManipulator
{
    class MainClass
    {
        public static void Main(string[] args)
        {
            List<int> numbers = Console.ReadLine()
                                       .Split(' ')
                                       .Select(int.Parse)
                                       .ToList();

            List<string> commands = Console.ReadLine()
                                           .Split(' ')
                                           .ToList();

            while (commands[0] != "print")
            {
                if (commands[0] == "add")
                {
                    int index   = int.Parse(commands[1]);
                    int element = int.Parse(commands[2]);
                    numbers.Insert(index, element);
                }
                else if (commands[0] == "addMany")
                {
                    int index = int.Parse(commands[1]);
                    numbers.InsertRange(index, commands
                                                 .Skip(2)
                                                 .Select(int.Parse));
                }
                else if (commands[0] == "contains")
                {
                    int element = int.Parse(commands[1]);
                    if (numbers.Contains(element))
                    {
                        Console.WriteLine(numbers.IndexOf(element));
                    }
                    else
                    {
                        Console.WriteLine(-1);
                    }
                }
                else if (commands[0] == "remove")
                {
                    int index = int.Parse(commands[1]);
                    numbers.RemoveAt(index);
                }
                else if (commands[0] == "shift")
                {
                    int position = int.Parse
                                      (commands[1]) % numbers.Count;
                    var helper = numbers.Skip(position).ToList();
                    for (int i = 0; i < position ; i++)
                    {
                        helper.Add(numbers[i]);
                    }
                    numbers = helper;
                }
                else if (commands[0] == "sumPairs")
                {
                    int lenght = numbers.Count / 2;

                    for (int i = 0; i < lenght; i++)
                    {
                        numbers[i] += numbers[i + 1];
                        numbers.RemoveAt(i + 1);
                    }
                }
                commands = Console.ReadLine()
                                           .Split(' ')
                                           .ToList();
            }
            Console.WriteLine("[" + string.Join(", ",numbers) + "]");
        }
    }
}