#include <bits/stdc++.h>
using namespace std;
int press(string p);
string guess_sequence(int len)
{
string ret = "";
string keys = "ABXY";
char first_car;
if (press("AB"))
{
if (press("A"))
first_car = 'A';
else
first_car = 'B';
}
else
{
if (press("X"))
first_car = 'X';
else
first_car = 'Y';
}
ret += first_car;
string keys_left = "";
for (auto c : keys)
if (c != first_car)
keys_left += c;
for (int nb_trouve(2); nb_trouve < len; ++nb_trouve)
{
string ask = "";
for (auto c : keys_left)
ask += ret + keys_left[0] + c;
ask += ret + keys_left[1];
int nb = press(ask);
if (nb == nb_trouve - 1)
ret += keys_left[2];
if (nb == nb_trouve)
ret += keys_left[1];
if (nb == nb_trouve + 1)
ret += keys_left[0];
}
if (len > 1)
{
if (press(ret + keys_left[0]) == len)
ret += keys_left[0];
else
{
if (press(ret + keys_left[1]) == len)
ret += keys_left[1];
else
ret += keys_left[2];
}
}
return ret;
}
