#include "combo.h"
//author: erray
#include <bits/stdc++.h>
using namespace std;
#ifdef DEBUG
#include "/home/ioi/codes/debug.h"
#else
#define debug(...) (void) 37
#endif
string M = "ABXY";
std::string guess_sequence(int N) {
int p = 2 * (press(string(2 * N, M[0]) + string(2 * N, M[1])) == 0);
p += press(string(4 * N, M[p + 1]));
char first = M[p];
string ans = ""s + M[p];
M.erase(find(M.begin(), M.end(), M[p]));
for (int i = 1; i < N - 1; ++i) {
string ask;
ask += ans + M[1];
for (int c = 0; c < 3; ++c) {
ask += ans + M[2] + M[c];
}
ask += string(4 * N - int(ask.size()), first);
ans += M[press(ask) - i];
}
if (N > 1) {
char last = M[2];
for (int i = 0; i < 2; ++i) {
string ask = ans + M[i];
if (press(ask + ask + ask + ask) == N) {
last = M[i];
}
}
ans += last;
}
return ans;
}
