SoftUni Fundamentals - School Library

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

namespace School_Library
{
    class Program
    {
        static void Main(string[] args)
        {
            List<string> books = Console.ReadLine().Split("&").ToList();
            string command = Console.ReadLine();

            while (command != "Done")
            {
                string[] splittedCommand = command.Split(" | ").ToArray();

                switch (splittedCommand[0])
                {
                    case "Add Book":
                        if (!books.Contains(splittedCommand[1]))
                        {
                            books.Insert(0, splittedCommand[1]);
                        }
                        break;
                    case "Take Book":
                        if (books.Contains(splittedCommand[1]))
                        {
                            books.Remove(splittedCommand[1]);
                        }
                        break;
                    case "Swap Books":
                        if (books.Contains(splittedCommand[1]) && books.Contains(splittedCommand[2]))
                        {
                            int indexOfFirstBook = books.IndexOf(splittedCommand[1]);
                            int indexOfSecondBook = books.IndexOf(splittedCommand[2]);
                            string temp = books[indexOfFirstBook];

                            books[indexOfFirstBook] = splittedCommand[2];
                            books[indexOfSecondBook] = temp;
                        }
                        break;
                    case "Insert Book":
                        books.Add(splittedCommand[1]);
                        break;
                    case "Check Book":
                        if (books.ElementAtOrDefault(int.Parse(splittedCommand[1])) != null)
                        {
                            string searchedBook = books.ElementAt(int.Parse(splittedCommand[1]));
                            Console.WriteLine(searchedBook);
                        }
                        break;
                }
                command = Console.ReadLine();
            }

            Console.WriteLine(string.Join(", ", books));
        }
    }
}