#include <bits/stdc++.h>
#include "combo.h"
using namespace std;
using ll = long long;
#define el '\n'
string guess_sequence(int N) {
vector<char> lst_c = { 'A', 'B', 'X', 'Y' };
string cur = "";
if (press(cur + "AB") >= cur.size() + 1) {
if (press(cur + "A") >= cur.size() + 1) cur += "A";
else cur += "B";
}
else {
if (press(cur + "X") >= cur.size() + 1) cur += "X";
else cur += "Y";
}
lst_c.erase(find(lst_c.begin(), lst_c.end(), cur[0]));
while ((int)cur.size() <= N - 2) {
string tmp = "";
tmp += cur + lst_c[0];
tmp += cur + lst_c[1] + lst_c[0];
tmp += cur + lst_c[1] + lst_c[1];
tmp += cur + lst_c[1] + lst_c[2];
int cnt = press(tmp), sz = cur.size();
if (cnt == sz + 1) {
cur += lst_c[0];
}
else if (cnt == sz + 2) {
cur += lst_c[1];
}
else {
cur += lst_c[2];
}
// cout << cur << el;
}
while ((int)cur.size() < N) {
for (char c: lst_c) {
if (press(cur + c) == (int)cur.size() + 1) {
cur += c;
break;
}
}
}
return cur;
}
