#include <bits/stdc++.h>
using namespace std;
#define pb push_back
#define ld long double
#define ll long long
#define sz(x) (int((x).size()))
#define all(x) (x).begin(), (x).end()
#define rall(x) (x).rbegin(), (x).rend()
#define uniq(x) x.resize(unique(all(x)) - x.begin());
#define lb lower_bound
#define ub upper_bound
int press(std::string p);
std::string guess_sequence(int N) {
string pref = "";
int ans = press("AB"), it = 0;
if(ans == 2) {
pref += "AB", it = 2;
} else if(ans == 1) {
ans = press("A");
if(ans == 1) {
pref += "A";
} else {
pref += "B";
}
it = 1;
} else {
ans = press("X");
if(ans == 1) {
pref += "X";
} else {
pref += "Y";
}
it = 1;
}
if(N == sz(pref)) {
return pref;
}
vector<char> vi;
for(auto i: {'X', 'Y', 'A', 'B'}) {
if(pref[0] != i) {
vi.push_back(i);
}
}
//
for(int i = it; i < N - 1; i++) {
string harc = pref + vi[0] + pref + vi[1] + vi[0] + pref + vi[1] + vi[1] + pref + vi[1] + vi[2];
ans = press(harc);
if(ans == i) {
pref += vi[2];
} else if(ans == (i + 1)) {
pref += vi[0];
} else if(ans == (i + 2)) {
pref += vi[1];
}
}
// cout << pref << endl;
int ans1 = press(pref + vi[0]);
if(ans1 == N) {
return (pref + vi[0]);
}
int ans2 = press(pref + vi[1]);
if(ans2 == N) {
return (pref + vi[1]);
}
return (pref + vi[2]);
}
