#include <bits/stdc++.h>
#include "combo.h"
using namespace std;
#define ll long long
#define F first
#define S second
#define pb push_back
#define pii pair<int, int>
const int N = 1e6;
int press(string s);
string guess_sequence(int N) {
string res = "";
vector<char> c = {'A', 'B', 'X', 'Y'};
if (press("AB")) {
if (press("A")) {
res += "A";
}
else res += "B";
}
else {
if (press("X")) {
res += "X";
}
else res += "Y";
}
c.erase(find(c.begin(), c.end(), res[0]));
for (int i = 1; i <= N - 2; i++) {
string ask = res;
ask.pb(c[2]);
ask.pb(c[1]);
ask = ask + res;
ask.pb(c[2]);
ask.pb(c[0]);
ask = ask + res;
ask.pb(c[2]);
ask.pb(c[2]);
ask = ask + res;
ask.pb(c[1]);
int x = press(ask);
res += c[x - i];
// cout << ask << '\n';
// cout << res << '\n';
}
if (press(res + "A" + res + "B") == N) {
if (press(res + "A") == N) {
res += "A";
}
else res += "B";
}
else {
if (press(res + "X") == N) {
res += "X";
}
else {
res += "Y";
}
}
return res;
}
