#include <bits/stdc++.h>
using namespace std;
int press(string p);
string guess_sequence(int n) {
string s = "", test;
const vector<char> letters = {'A', 'B', 'X', 'Y'};
if (press("AB") >= 1) {
if (press("A") >= 1) {
s += 'A';
} else {
s += 'B';
}
} else {
if (press("Y") >= 1) {
s += 'Y';
} else {
s += 'X';
}
}
while ((int)s.size() < n) {
bool avance = false;
for (char c : letters) {
if (c == s[0]) {
continue;
}
test = s + c;
int r = press(test);
if (r == (int)s.size() + 1) {
s += c;
avance = true;
break;
}
}
if (!avance) {
break;
}
}
return s;
}
