#include <bits/stdc++.h>
using namespace std;
int press(string p);
string guess_sequence(int n) {
string s;
if (press("AB") >= 1) {
s = (press("A") >= 1) ? "A" : "B";
} else {
s = (press("X") >= 1) ? "X" : "Y";
}
vector<char> all = {'A','B','X','Y'};
vector<char> rest;
for (char ch : all) if (ch != s[0]) rest.push_back(ch);
char a = rest[0], b = rest[1], c = rest[2];
while ((int)s.size() < n - 1) { // on s'arrête avant la dernière
string q = s + a + a + s + a + b;
int r = press(q);
if (r == (int)s.size()) {
s.push_back(c);
} else if (r == (int)s.size() + 1) {
s.push_back(a);
} else {
s.push_back(b);
}
}
if ((int)s.size() < n) {
if (press(s + a) == n) s.push_back(a);
else if (press(s + b) == n) s.push_back(b);
else s.push_back(c);
}
return s;
}
