#include <bits/stdc++.h>
#include "combo.h"
using namespace std;
string guess_sequence(int N) {
// guess first character;
string T;
if(press("AB")) {
if(press("A")) T = "A";
else T = "B";
} else {
if(press("X")) T = "X";
else T = "Y";
}
vector<char> ch;
if(T != "A") ch.push_back('A');
if(T != "B") ch.push_back('B');
if(T != "X") ch.push_back('X');
if(T != "Y") ch.push_back('Y');
// guess n-2 characters;
for(int i = 0; i < N-2; i++) {
int r = press(T + ch[0] + T + ch[1] + ch[0] + T + ch[1] + ch[1] + T + ch[1] + ch[2]);
if(r == T.length()) T.push_back(ch[2]);
else if(r == T.length() + 1) T.push_back(ch[0]);
else T.push_back(ch[1]);
}
// guess last characters
if(press(T + ch[0]) == N) T.push_back(ch[0]);
else if(press(T + ch[1]) == N) T.push_back(ch[1]);
else T.push_back(ch[2]);
return T;
}
