#include "combo.h"
#include <bits/stdc++.h>
using namespace std;
string guess_sequence(int N) {
char k;
if (press("AB") > 0) {
if (press("B") > 0) k = 'B';
else k = 'A';
} else {
if (press("X") > 0) k = 'X';
else k = 'Y';
}
vector<char> v;
for (char c : {'A','B','X','Y'}) {
if (c != k) v.push_back(c);
}
string S(1, k);
for (int i = 1; i < N-1; i++) {
int res = press(S + v[0]);
if (res == i+1) {
S += v[0];
continue;
}
res = press(S + v[1]);
if (res == i+1) {
S += v[1];
continue;
}
S += v[2];
}
if (N > 1) {
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;
}
