#include <bits/stdc++.h>
#include <ext/pb_ds/assoc_container.hpp>
#include <ext/pb_ds/tree_policy.hpp>
#include "combo.h"
#define mp make_pair
#define pb push_back
#define ppb pop_back
#define pf push_front
#define ppf pop_front
#define eb emplace_back
#define st first
#define nd second
#define vt vector
#define VAR(__var) #__var << ": " << __var << " "
#define PAIR(__var) #__var << ": " << __var.first << ", " << __var.second << " "
#define FOR(__var, __start, __end) for(int __var=__start; __var<__end; ++__var)
#define FORB(__var, __start, __end) for(int __var=__start; __var>__end; --__var)
#define REP(__var, __cnt) for(int __var=0; __var<(__cnt); ++__var)
#define EACH(__var, __x) for(auto __var : __x)
#define maxi(__x, __y) __x = (__x>__y?__x:__y)
#define mini(__x, __y) __x = (__x<__y?__x:__y)
#define all(__var) (__var).begin(),(__var).end()
#define rall(__var) (__var).rbegin(),(__var).rend()
#define sz(__var) (int)(__var).size()
using namespace std;
using namespace __gnu_pbds;
template <typename T>
using ord_set = tree<T,null_type,less<T>,rb_tree_tag,tree_order_statistics_node_update>;
#ifdef DEBUG
template<typename Stream, typename T1, typename T2>
Stream& operator << (Stream& out, pair<T1, T2> a) {return out << "(" << a.st << ", " << a.nd << ")";}
template<typename Stream, typename T>
Stream &operator << (Stream& out, T v) {
out << "{";
int i = 0;
for (auto x : v)
out << x << ((++ i) != sz(v) ? ", " : "");
return out << "}";
}
template<typename... Args>
void dump(Args... x) {((cerr << x << ", "), ...) << '\n';}
#define debug(x...) cerr << "[" #x "]: ", dump(x)
#else
#define debug(...) 0
#endif
typedef long long ll;
typedef long double ld;
typedef pair<ll, ll> pll;
typedef pair<int, int> pii;
const bool __test_cases = false;
const int INF = 1e9+2137;
string guess_sequence(int N) {
string now;
mt19937 rng(213769);
vt<string> ord = {"X", "A", "Y", "B"};
shuffle(all(ord), rng);
for(auto c : ord) {
int got = press(c);
if(got == 1) {
now = c;
break;
}
}
vt<string> tmp;
for(auto x : ord)
if(x != now)
tmp.pb(x);
swap(tmp, ord);
int prev = 1;
while(sz(now) < N) {
shuffle(all(ord), rng);
string q;
for(auto c : ord)
q += now + ord[0] + c;
q += now + ord[1];
if(sz(q) > 4*N) {
for(auto c : ord) {
int got = press(now + c);
if(got == prev+1) {
now += c;
++prev;
break;
}
}
continue;
}
int got = press(q);
cerr << "now: " << now << '\n';
cerr << "press: " << q << '\n';
cerr << "got: " << got << '\n';
if(got == prev)
++prev, now += ord[2];
else if(got == prev+1)
++prev, now += ord[1];
else
++prev, now += ord[0];
}
return now;
}
