n_opperations = int(input().strip())
operations = list()

for _ in range(n_opperations):
    operations.append(input().strip())

string = str()
done = list()

for ops in operations:
    if ops[0] == '1':
        done.append(ops)
        string += ops[2:]
    elif ops[0] == '2':
        k = int(ops[2:])
        done.append((ops[0], ' ', string[-k:]))
        string = string[:-k]
    elif ops[0] == '3':
        print(string[int(ops[2:])-1])
    elif ops[0] == '4':
        if done[-1][0] == '1':
            string = string[:-len(done[-1][2:])]
            done.pop()
        else:
            string += done[-1][2]
            done.pop()

class text_editor:
    def __init__(self):
        self.S = ""
        self.op_stack = []
        self.tgt_stack = []
           
    def w_append(self,tgt):
        s1 = list(self.S)
        s1.append(tgt)
        self.S = ''.join(s1)
        self.op_stack.append('1')
        self.tgt_stack.append(len(tgt))
        
    def k_delete(self,tgt):
        s1 = list(self.S)
        self.tgt_stack.append(''.join(s1[-int(tgt):]))
        s1 = s1[:-int(tgt)]
        self.S = ''.join(s1)
        self.op_stack.append('2')
        
    def k_print(self,tgt):
        s1 = list(self.S)
        print(f'{s1[int(tgt) -1]}')

    def undo(self):
        s1 = list(self.S)
        op = self.op_stack.pop(-1)
        if op == '1':
            s1 = s1[:-int(self.tgt_stack.pop(-1))]
        elif op == '2':
            s1.append(self.tgt_stack.pop(-1))
        if s1:
            self.S = ''.join(s1)
        else:
            self.S = ""
        
    def receive_ops(self,op,tgt):
        if op == '1':
            self.w_append(tgt)

        elif op == '2':
            self.k_delete(tgt)

        elif op == '3':
            self.k_print(tgt)
        elif op == '4':
            self.undo()
                   
if __name__ == '__main__':
    q = int(input())
    S = ""
    tgt = None
    op = ''
    t = text_editor()
    for _ in range(q):
        x = input().split()
        op = x[0]
        if len(x) > 1:
            tgt = x[1]
        t.receive_ops(op,tgt)

my c++ sol:

#include <cmath>
#include <cstdio>
#include <vector>
#include <iostream>
#include <algorithm>
#include <stack>
using namespace std;


int main() {
    /* Enter your code here. Read input from STDIN. Print output to STDOUT */
    string s="";
    stack<string> st;
    int n;
    cin>>n;
    for(int i =0; i< n; i++)
    {
        int k =0;
        cin>>k;
        if(k==1)
        {
            string str;
            cin>>str;
            st.push(s);
            s.append(str);
        }
        if(k==2)//last k character
        {
            int no;
            cin>>no;
            st.push(s);
            while(no>0)
            {
                s.pop_back();
                no--;
            }
        }
        if(k==3)//print kth char
        {
            int h;
            cin>>h;
            cout<<s[h-1]<<endl;
        }
        else if (k == 4) {
            if (!st.empty()) {
                s = st.top();
                st.pop();
            }
        }
    }
    return 0;
}

int main() {
    /* Enter your code here. Read input from STDIN. Print output to STDOUT */   
    int q=0;
    cin >> q;
    string s ="";
    stack<string> v;
    v.push(s);
    for(int i=0; i<q; i++){
        int op = 0;string ss;
        cin >> op;
        if(op != 4)cin >> ss;
        switch (op) {
            case 1:
               s+=ss;
               v.push(s);
               break;
            case 2:
                s = s.substr(0, s.length() - stoi(ss));
                v.push(s);
                break;
             case 3:
                cout << v.top()[stoi(ss)-1]<<endl;
                break;
            case 4:
                v.pop();
                s = v.top();
                break;
        }
    }
    
    return 0;
}

import java.io.*;
import java.util.*;
import java.text.*;
import java.math.*;
import java.util.regex.*;

public class Solution {

    public static void main(String[] args) {
      
        Scanner sc = new Scanner(System.in);
        String str = "";
        int top = 0;
        int q = Integer.parseInt(sc.nextLine());
        MyStack stack = new MyStack(q);
        for(int i = 0; i < q; ++i){
            String st[] = sc.nextLine().split(" ");
            int query = Integer.parseInt(st[0]);
            if(query == 1){
                Node newNode = new Node(query,str.length());
                stack.top++;
                stack.list[stack.top] = newNode;
                str += st[1];
            } else if(query == 2){
                int k = Integer.parseInt(st[1]);
                Node newNode = new Node(query,str.substring(str.length()-k));
                stack.top++;
                stack.list[stack.top] = newNode;
                str = str.substring(0,str.length()-k);
            } else if(query == 3){
                int index = Integer.parseInt(st[1]);
                System.out.println(str.charAt(index-1));
            } else if(query == 4){
                Node newNode = stack.list[stack.top];
                stack.top--;
                if(newNode.qtype == 1){
                    str = str.substring(0,newNode.idx);
                } else if(newNode.qtype == 2){
                    str += newNode.w;
                }
            }
        }
    }
}
class MyStack{
    Node list[];
    int top;
    MyStack(int size){
        this.list = new Node[size];
        this.top = -1;
    }
}
class Node{
    int qtype;
    int idx;
    String w;
    Node(int x, String y){
        this.qtype = x;
        this.w = y;
    }
    Node(int x, int index){
        this.qtype = x;
        this.idx = index;
    }
}