#include <bits/stdc++.h>
using namespace std;
int press(string p);
string guess_sequence(int n) {
string but = "AB";
string res = "";
if (!press(but)) but = "XY";
char ff = but[0];
if (!press(but.substr(0, 1))) ff = but[1];
but = "ABXY";
string bt = "";
for (char c : but) {
if (c == ff) continue;
bt += c;
}
res += ff;
if (n <= 1) {
return res;
}
for (int i = 1; i < n; i++) {
res += bt[press(res + bt[1] + res + bt[2] + bt[0] + res + bt[2] + bt[1] + res + bt[2] + bt[2]) - res.size()];
}
return res;
}
