#include "combo.h"
#include <set>
#include <iostream>
using namespace std;
string guess_sequence(int N) {
string S = "";
set<char> a = {'A', 'B', 'X', 'Y'};
string p = "";
if (press("A") == 1){
a.erase('A');
S += 'A';
} else if (press("B") == 1){
a.erase('B');
S += 'B';
} else if (press("X") == 1){
a.erase('X');
S += 'X';
} else{
a.erase('Y');
S += 'Y';
}
char v[3];
int idx = 0;
if (a.count('A')) v[idx++] = 'A';
if (a.count('B')) v[idx++] = 'B';
if (a.count('X')) v[idx++] = 'X';
if (a.count('Y')) v[idx++] = 'Y';
while ((int) S.size() < N-1){
p = S + v[0] + S + v[1]+v[0] + S + v[1]+v[1] + S + v[1]+v[2];
int coins = press(p);
if (coins == (int)S.size()+2){
S += v[1];
} else if (coins == (int)S.size()+1){
S += v[0];
} else {
S += v[2];
}
}
if (N == 1) return S;
if (press(S+v[0]) == N){
S += v[0];
} else if (press(S+v[1]) == N){
S += v[1];
} else{
S += v[2];
}
return S;
}
