#include <bits/stdc++.h>
using namespace std;
int press(string p);
string guess_sequence(int n) {
string a = "";
vector<string> s{"A", "B", "X", "Y"};
if (press("AB")) {
if (press("A")) a += "A";
else a += "B";
}
else {
if (press("X")) a += "X";
else a += "Y";
}
s.erase(find(s.begin(), s.end(), a));
for (int i = 2; i < n; ++i) {
int x = press(a + s[0] + a + s[1] + s[0] + a + s[1] + s[1] + a + s[1] + s[2]);
if (x == a.size()) a += s[2];
else if (x == a.size() + 1) a += s[0];
else a += s[1];
}
if (n > 1) {
if (press(a + s[0]) > a.size()) a += s[0];
else if (press(a + s[1]) > a.size()) a += s[1];
else a += s[2];
}
return a;
};
