// EXPLOSION!
#define _CRT_SECURE_NO_WARNINGS
#include<bits/stdc++.h>
#include<unordered_set>
#include<unordered_map>
#include<chrono>
using namespace std;
typedef pair<int, int> pii;
typedef long long ll;
typedef pair<ll, ll> pll;
typedef long double ld;
typedef vector<int> vi;
typedef vector<ll> vll;
typedef vector<pair<int, int>> vpi;
typedef vector<pair<ll, ll>> vpll;
#define FOR(i,a,b) for (int i = (a); i < (b); ++i)
#define F0R(i,a) FOR(i,0,a)
#define ROF(i,a,b) for (int i = (b)-1; i >= (a); --i)
#define R0F(i,a) ROF(i,0,a)
#define trav(a,x) for (auto& a: x)
#define pb push_back
#define mp make_pair
#define rsz resize
#define sz(x) int(x.size())
#define all(x) x.begin(),x.end()
#define f first
#define s second
#define cont continue
#define endl '\n'
//#define ednl '\n'
#define test int testc;cin>>testc;while(testc--)
#define pr(a, b) trav(x,a)cerr << x << b; cerr << endl;
#define message cout << "Hello World" << endl;
const int dx[4] = { 1,0,-1,0 }, dy[4] = { 0,1,0,-1 }; // for every grid problem!!
const ll linf = 4000000000000000000LL;
const ll inf = 1000000007;//998244353
void pv(vi a) { trav(x, a)cout << x << " "; cout << endl; }void pv(vll a) { trav(x, a)cout << x << " "; cout << endl; }void pv(vector<vi>a) {
F0R(i, sz(a)) { cout << i << endl; pv(a[i]); cout << endl; }
}void pv(vector<vll>a) { F0R(i, sz(a)) { cout << i << endl; pv(a[i]); }cout << endl; }void pv(vector<string>a) { trav(x, a)cout << x << endl; cout << endl; }
void setIO(string s) {
ios_base::sync_with_stdio(0); cin.tie(0);
if (sz(s))
{
freopen((s + ".in").c_str(), "r", stdin);
if (s != "test1")
freopen((s + ".out").c_str(), "w", stdout);
}
}
#ifndef arwaeystoamneg
//#include "elephants.h"
#endif
const int MAX = 1000005, SZ = 21;
struct T
{
char x;
int len, jump[SZ];
T()
{
x = '@';
len = -inf;
fill(jump, jump + SZ, -inf);
}
};
T* a[MAX];
int cur = 0, b[MAX];
int i = 1;
void init(char L, int p)
{
a[cur] = new T();
a[cur]->x = L;
a[cur]->jump[0] = p;
F0R(i, SZ - 1)a[cur]->jump[i + 1] = (a[cur]->jump[i] == -1 ? -1 : a[a[cur]->jump[i]]->jump[i]);
a[cur]->len = (p == -1 ? 0 : a[p]->len + 1);
cur++;
}
void Init()
{
init('$', -1);
b[0] = 0;
}
void TypeLetter(char L)
{
init(L, b[i - 1]);
b[i] = cur - 1;
i++;
}
void UndoCommands(int U)
{
b[i] = b[i - U - 1];
i++;
}
char query(int x, int p)
{
R0F(i, SZ)
{
if (p & (1 << i))
{
x = a[x]->jump[i];
}
}
return a[x]->x;
}
char GetLetter(int P)
{
return query(b[i - 1], a[b[i - 1]]->len - P - 1);
}
#ifdef arwaeystoamneg
int main() {
setIO("test1");
Init();
int cmd_num;
int tmp = scanf("%d", &cmd_num);
assert(tmp == 1);
int i;
for (i = 0; i < cmd_num; i++) {
char cmd;
tmp = scanf(" %c", &cmd);
assert(tmp == 1);
if (cmd == 'T') {
char letter;
tmp = scanf(" %c", &letter);
assert(tmp == 1);
TypeLetter(letter);
}
else if (cmd == 'U') {
int number;
tmp = scanf("%d", &number);
assert(tmp == 1);
UndoCommands(number);
}
else if (cmd == 'P') {
int index;
char letter;
tmp = scanf("%d", &index);
assert(tmp == 1);
letter = GetLetter(index);
printf("%c\n", letter);
}
}
puts("Let's test for cheating!!");
return 0;
}
#endif
