#include <bits/stdc++.h>
#include <ext/rope>
#define ll long long int
using namespace std;
const ll sz = 1e6+1;
__gnu_cxx::crope memo[sz];
ll currInd = 0;
void Init() {}
void TypeLetter(char L) {
memo[currInd+1] = memo[currInd]+L;
currInd++;
}
void UndoCommands(int U) {
memo[currInd+1] = memo[currInd-U];
currInd++;
}
char GetLetter(int P) {
return memo[currInd][P];
}
void solve() {
char cmd; cin >> cmd;
if (cmd == 'T') {
char letter; cin >> letter;
TypeLetter(letter);
}
else if (cmd == 'U') {
int number; cin >> number;
UndoCommands(number);
}
else if (cmd == 'P') {
int index; cin >> index;
char letter;
letter = GetLetter(index);
cout << letter << endl;
}
}
//int main() {
// int tc; cin >> tc;
// while (tc--) solve();
//}
