#include "combo.h"
#include <bits/stdc++.h>
using namespace std;
string guess_sequence(int N) {
string s = "AB", t, d;
int res = press(s);
if (res) {
s = "A";
res = press(s);
t = res ? "A" : "B";
} else {
s = "X";
res = press(s);
t = res ? "X" : "Y";
}
if (N == 1) return t;
for (auto& x : {'A', 'B', 'X', 'Y'}) if (x != t[0]) d.push_back(x);
for (int i = 1; i < N-1; i++) {
s = t;
s.push_back(d[0]);
s += t;
s.push_back(d[1]);
s.push_back(d[0]);
s += t;
s.push_back(d[1]);
s.push_back(d[1]);
s += t;
s.push_back(d[1]);
s.push_back(d[2]);
res = press(s);
if (res <= i) t.push_back(d[2]);
else if (res == i+1) t.push_back(d[0]);
else t.push_back(d[1]);
}
for (int i = 0; i < 2; i++) {
s = t;
s.push_back(d[i]);
res = press(s);
if (res == N) t.push_back(d[i]);
}
if ((int) t.size() < N) t.push_back(d[2]);
cout << t << '\n';
return t;
}
