#include <bits/stdc++.h>
#define ll long long
#define pb push_back
#define fi first
#define se second
#define lf (id<<1)
#define rg ((id<<1)|1)
#define md ((l+r)>>1)
#define ld long double
using namespace std;
typedef pair<int,int> pii;
typedef pair<pii, int> ipii;
const int MAXN = 1e6+10;
const int LOG = 20;
const int MOD = 998244353;
const int SQRT = 450;
const vector<int> NOL = {};
mt19937 rng(chrono::steady_clock::now().time_since_epoch().count());
const vector<int> dx = {1, -1, 0, 0};
const vector<int> dy = {0, 0, 1, -1};
int anc[MAXN][LOG+3];
char val[MAXN];
int siz[MAXN];
int nw = 0;
void Init(){}
void TypeLetter(char L) {
nw++; val[nw] = L;
anc[nw][0] = nw-1; siz[nw] = siz[nw-1]+1;
for(int i=1; i<LOG; i++){
anc[nw][i] = anc[ anc[nw][i-1] ][i-1];
}
// cout << nw << ' ' << val[nw] << "nw\n";
}
void UndoCommands(int U) {
nw++;
val[nw] = val[nw-U-1]; siz[nw] = siz[nw-U-1];
for(int i=0; i<LOG; i++){
anc[nw][i] = anc[nw-U-1][i];
}
}
char GetLetter(int P) {
int up = siz[nw]-P-1;
int ret = nw;
for(int i=LOG-1; i>=0; i--){
if((up>>i) & 1) ret = anc[ret][i];
}
return val[ret];
}
