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

namespace _03._School_Library
{
    class Program
    {
        static void Main(string[] args)
        {
            List<string> booksLibrary = Console.ReadLine().Split('&').ToList();
            string input = Console.ReadLine();

            while (input != "Done")
            {
                string[] spllited = input.Split(" | ");
                if (spllited[0] == "Add Book")
                {
                    string bookName = spllited[1];
                    if (!booksLibrary.Contains(bookName))
                    {
                        booksLibrary.Insert(0, bookName); //добавя книга на първа позиция;
                    }
                }
                else if (spllited[0] == "Take Book")
                {
                    string bookName = spllited[1];
                    if (booksLibrary.Contains(bookName))
                    {
                        booksLibrary.Remove(bookName);
                    }
                }
                else if (spllited[0] == "Swap Books")
                {
                    string bookName = spllited[1];
                    string secondBokk = spllited[2];
                    if (booksLibrary.Contains(bookName) && booksLibrary.Contains(secondBokk))
                    {
                        int indexfirst = booksLibrary.IndexOf(bookName);
                        int indexSecond = booksLibrary.IndexOf(secondBokk);
                        string temp1 = booksLibrary[indexfirst];
                        string temp2 = booksLibrary[indexSecond];
                        booksLibrary[indexfirst] = temp2;
                        booksLibrary[indexSecond] = temp1;

                    }
                }
                else if (spllited[0] == "Insert Book")
                {
                    // тук проверката за съдържаща се книга е излишна. Няма условие да се добави, само ако я няма вече в списъка.
                    string bookName = spllited[1];
                    booksLibrary.Add(bookName);
                }
                else if (spllited[0] == "Check Book")
                {
                    int index = int.Parse(spllited[1]);
                    if (index >= 0 && index <= booksLibrary.Count)
                    {
                        Console.WriteLine($"{booksLibrary[index]}");
                    }
                }
                input = Console.ReadLine();
            }
            Console.WriteLine(string.Join(", ", booksLibrary));
        }
    }
}