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

namespace Simple_Text_Editor
{
    class Program
    {
        static void Main(string[] args)
        {
            int numOpper = int.Parse(Console.ReadLine());
            StringBuilder currentText = new StringBuilder(string.Empty);
            StringBuilder printText = new StringBuilder();
            Stack<StringBuilder> stack = new Stack<StringBuilder>();

            for (int i = 0; i < numOpper; i++)
            {
                string[] input = Console.ReadLine().Split(' ', StringSplitOptions.RemoveEmptyEntries);
                int command = int.Parse(input[0]);

                switch (command)
                {
                    case 1:
                        stack.Push(currentText);
                        currentText = new StringBuilder(currentText.ToString());
                        currentText.Append(input[1]);
                        break;
                    case 2:
                        stack.Push(currentText);
                        int count = int.Parse(input[1]);

                        if (count >= currentText.Length)
                        {
                            currentText = new StringBuilder(string.Empty);
                        }
                        else
                        {
                            string newText = currentText.ToString().Substring(0, currentText.Length - count);
                            currentText = new StringBuilder(newText);
                        }
                        break;
                    case 3:
                        int index = int.Parse(input[1]);
                        if (((index - 1) < currentText.Length) && ((index - 1) >= 0))
                        {
                            printText.AppendLine(currentText[index - 1].ToString());
                        }
                        break;
                    case 4:
                        currentText = new StringBuilder(stack.Pop().ToString());
                        break;

                    default:
                        break;
                }
            }
            Console.WriteLine(printText.ToString());
        }
    }
}