using System;
using System.Collections.Generic;
using System.Text;

namespace P09SimpleTextEditor
{
    class Program
    {
        static void Main(string[] args)
        {
            StringBuilder sb = new StringBuilder();
            var unchangedText = new Stack<string>();

            int numberOfCommands = int.Parse(Console.ReadLine());

            for (int i = 0; i < numberOfCommands; i++)
            {
                string[] command = Console.ReadLine().Split();

                if (command[0] == "1")
                {
                    unchangedText.Push(sb.ToString());

                    string textToAdd = command[1];
                    sb.Append(textToAdd);
                   // Console.WriteLine(sb);
                }
                else if (command[0] == "2")
                {
                    unchangedText.Push(sb.ToString());

                    int symbolsToDelete = int.Parse(command[1]);

                    if (symbolsToDelete >= sb.Length)
                    {
                        symbolsToDelete = sb.Length;
                        sb.Clear();
                    }
                    else
                    {
                        sb.Remove(sb.Length - symbolsToDelete, symbolsToDelete);

                    }
                    //Console.WriteLine(sb);
                }
                else if (command[0] == "3")
                {
                    int indexToGet = int.Parse(command[1]);

                    if (sb.Length == 0)
                    {
                        break;
                    }

                    if (indexToGet >= sb.Length)
                    {
                        indexToGet = sb.Length;
                    }

                    string tempText = sb.ToString();
                    Console.WriteLine($"{tempText[indexToGet-1]}");

                }
                else if(command[0] == "4")
                {
                    string tempText = sb.ToString();
                    tempText = unchangedText.Pop();
                    sb.Clear();
                    sb.Append(tempText);

                }

            }



        }
    }
}