import java.util.ArrayDeque;
import java.util.Deque;
import java.util.Scanner;

public class SimpleTextEditor {
    public static void main(String[] args) {
        Scanner scanner=new Scanner(System.in);

        int n=Integer.parseInt(scanner.nextLine());

StringBuilder text=new StringBuilder();
        Deque<StringBuilder> stack=new ArrayDeque<>();

        while (n-->0){
            String[] tokens=scanner.nextLine().split("\\s+");

            String commmand=tokens[0];
            switch (commmand){
                case "1":

            text.append(tokens[1]);
            stack.push(new StringBuilder(text));
                    break;
                case "2":
                    int count=Integer.parseInt(tokens[1]);
                    int start=text.length()-count;
                    text.delete(start,start+count);
                    stack.push(new StringBuilder(text));
                    break;
                case "3":

                    System.out.println(text.charAt(Integer.parseInt(tokens[1])));
                    break;
                case "4":
                    if(stack.size()>1) {
                        stack.pop();
                        text = stack.peek();
                    }
                    break;

            }
        }
    }
}