#pragma GCC optimize("-O3")
#include<bits/stdc++.h>
#include<ext/pb_ds/assoc_container.hpp>
#include<ext/pb_ds/tree_policy.hpp>
#define ll long long
#define ld long double
#define vl vector<ll>
#define vi vector<int>
#define all(v) v.begin(), v.end()
#define rall(v) v.rbegin(), v.rend()
#define f first
#define s second
#define pii pair<int, int>
#define pll pair<ll, ll>
#define pb push_back
#define p_b pop_back
using namespace std;
using namespace __gnu_pbds;
typedef tree<ll, null_type, less_equal<ll>, rb_tree_tag, tree_order_statistics_node_update> ordered_set;
mt19937_64 rng(chrono::steady_clock::now().time_since_epoch().count());
char last;
string s = "";
vector<string>vect;
void Init() {
vect.pb(s);
}
void TypeLetter(char L) {
s += L;
vect.pb(s);
last = L;
}
void UndoCommands(int U) {
int sz = (int)(vect.size());
s = vect[sz - 1 - U];
vect.pb(s);
}
char GetLetter(int P) {
return s[P];
}
