#include "combo.h"
#include <bits/stdc++.h>
using namespace std;
vector<char> c(4), ch;
string guess_sequence(int N) {
string p;
if (press("AB")) press("A") ? p="A" : p="B";
else if (press("XY")) press("X") ? p="X" : p="Y";
c[0]='A', c[1]='B', c[2]='X', c[3]='Y';
for (auto x:c) if (x!=p[0]) ch.push_back(x);
if (N==1) return p;
for (int i=2; i<N; i++)
{
string tmp=p+ch[1];
for (auto x:ch) tmp+=p+ch[2]+x;
p+=ch[press(tmp)-i+1];
}
if (press(p+"A"+p+"B")==N) press(p+"A")==N ? p+="A" : p+='B';
else if (press(p+"X")==N) p+="X";
else p+="Y";
return p;
}
