#include <bits/stdc++.h>
#define ll long long
#define el cout << '\n'
using namespace std;
int press(string p);
string guess_sequence(int N)
{
string ch = "ABXY";
string ans = "";
if (press("AB"))
{
if (press("B"))
swap(ch[0], ch[1]);
}
else
{
if (press("X"))
swap(ch[0], ch[2]);
else
swap(ch[0], ch[3]);
}
ans = ch[0];
while (ans.size() < N - 1)
{
int state = press(ans + ch[1] + ch[1] + ans + ch[1] + ch[2] + ans + ch[1] + ch[3] + ans + ch[2]);
if (state == ans.size())
ans.push_back(ch[3]);
else if (state == ans.size() + 1)
ans.push_back(ch[2]);
else
ans.push_back(ch[1]);
}
if (press(ans + ch[1]) == N)
ans.push_back(ch[1]);
else if (press(ans + ch[2]) == N)
ans.push_back(ch[2]);
else
ans.push_back(ch[3]);
return ans;
}
