#include <iostream>
#include <algorithm>
#include<bits/stdc++.h>
using namespace std;

void append(string &s, string &w){
    s.append(w);
}

void deleteS(string &s, int k){
    if(s.length() == k)
        s.erase(s.begin(),s.end());
    else{
       k = s.length()-k;
       s = s.substr(0,k); 
    }    
}

void printK(string &s, int k){
    string :: iterator it;
    it = s.begin();
    advance(it,k-1);
    cout<<*it<<endl;
}

void undo(stack<string> &st, string &s){
    if(st.size() == 1){
        s = st.top();
        return;
    }
    if(!st.empty()){
        s = st.top();
        st.pop();
    }
}

int main() {
    /* Enter your code here. Read input from STDIN. Print output to STDOUT */  
    int q;
    stack<string> st;
    string s;
    cin>>q;
    while(q--){
        int x;
        string w;
        cin>>x;
        if(x==1){
            cin>>w;
            st.push(s);
            append(s,w);                        
        }
        if(x==2){
            int y;
            cin>>y;
            st.push(s);
            deleteS(s,y);            
        }
        if(x==3){
            int y;
            cin>>y;            
            printK(s,y);
        }
        if(x==4){
            undo(st,s);
        }
    } 
    return 0;
}