#include <bits/stdc++.h>
#define pb push_back
#define eb emplace_back
#define sz(x) (int)x.size()
#define all(x) x.begin(), x.end()
#define uniq(x) x.erase(unique(all(x)), x.end())
#define rall(x) x.rbegin(), x.rend()
//#define int long long
using namespace std;
using ll = long long;
using ull = unsigned long long;
using ld = long double;
using pii = pair<int, int>;
using pll = pair<ll, ll>;
const int mod = 1e9 + 7;
const int LOG = 20;
const int maxn = 1e5 + 5;
const double eps = 1e-9;
vector<string> v;
void Init() {
v.push_back("");
}
void TypeLetter(char ch) {
v.push_back(v.back());
v.back() += ch;
}
void UndoCommands(int U) {
v.push_back(v[sz(v)-U-1]);
}
char GetLetter(int p) {
return v[sz(v)-1][p];
}
