#include "combo.h"
#include<bits/stdc++.h>
using namespace std;
string guess_sequence(int N) {
string s = "";
if (press("AB")){
if (press("A")) s = "A";
else s = "B";
}
else {
if (press("X")) s = "X";
else s = "Y";
}
if (N == 1) return s;
vector<string> v;
if (s[0] != 'A') v.push_back("A");
if (s[0] != 'B') v.push_back("B");
if (s[0] != 'X') v.push_back("X");
if (s[0] != 'Y') v.push_back("Y");
while ((int) s.size() != N-1){
//cout << s+v[0]+s+v[1]+v[0]+s+v[1]+v[1]+s+v[1]+v[2] << endl;
int res = press(s+v[0]+s+v[1]+v[0]+s+v[1]+v[1]+s+v[1]+v[2]);
if (res == (int) s.size()) s += v[2];
if (res == (int) s.size()+1) s += v[0];
if (res == (int) s.size()+2) s += v[1];
}
if (press(s+v[0]+s+v[1]) == (int) s.size()+1){
if (press(s+v[0]) == (int) s.size()+1) s += v[0];
else s += v[1];
}
else s += v[2];
return s;
}
