Array Manipulator

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


class Program
{
    static void Main(string[] args)
    {

        List<int> nums = Console.ReadLine().Split(new[] { ' ' }, StringSplitOptions.RemoveEmptyEntries).Select(int.Parse).ToList();
        while (true)
        {
            var input = Console.ReadLine().Split(new[] { ' ' }, StringSplitOptions.RemoveEmptyEntries).ToList();
            if (input[0] == "print")
            {
                break;
            }
            switch (input[0])
            {
                case "add":
                    nums.Insert(int.Parse(input[1]), int.Parse(input[2]));
                    break;
                case "addMany":
                    for (int i = input.Count - 1; i >= 2; i--)
                    {
                        nums.Insert(int.Parse(input[1]), int.Parse(input[i]));
                    }
                    break;
                case "contains":
                    int contains = int.Parse(input[1]);
                    Console.WriteLine(nums.IndexOf(contains));
                    break;
                case "remove":
                    nums.RemoveAt(int.Parse(input[1]));
                    break;
                case "shift":
                    int positions = int.Parse(input[1]);
                    for (int i = 0; i < positions; i++)
                    {
                        int lastElement = nums[0];
                        for (int j = 0; j < nums.Count - 1; j++)
                        {
                            nums[j] = nums[j + 1];
                        }
                        nums[nums.Count - 1] = lastElement;
                    }
                    break;
                case "sumPairs":
                    List<int> sumPairs = new List<int>();
                    for (int i = 0; i < nums.Count - 1; i += 2)
                    {
                        sumPairs.Add(nums[i] + nums[i + 1]);
                    }
                    if (nums.Count % 2 == 1)
                    {
                        sumPairs.Add(nums[nums.Count - 1]);
                    }
                    nums = sumPairs;
                    break;
            }
        }
        Console.WriteLine("["+String.Join(", ", nums)+"]");
    }
}