#include <bits/stdc++.h>
#include "combo.h"
using namespace std;
string guess_sequence(int N){
string S = "";
int first = 5;
bool a;
char buttons[4] = {'A', 'B', 'X', 'Y'};
vector<char> b; // size of b = 3
for(int i = 0; i < 3; i++){
if(press(S + buttons[i]) > 0){
first = i;
S += buttons[i];
break;
}
}
if(first == 5){
first = 3;
S += buttons[3];
}
// Q = 3 at worst
for(int i = 0; i < 4; i++){
if(i != first){
b.push_back(buttons[i]);
}
}
for(int i = 1; i < N; i++){
a = false;
for(int i = 0; i < 2; i++){
if(press(S + b[i]) == i + 1){
S += b[i];
a = true;
break;
}
}
if(a == false){
S += b[2];
}
}
// Q = 2*(N - 1) + 3 at worst
return S;
}
