/**
* author: tourist
* created:
**/
#include "combo.h"
#include <bits/stdc++.h>
using namespace std;
#ifdef LOCAL
#include "algo/debug.h"
#else
#define debug(...) 42
#endif
vector<string> alphabet = {"A", "B", "X", "Y"};
string guess_sequence(int n) {
string firs = "?", ans;
for (int i = 0; i < 3; i++) {
if (press(alphabet[i]) == 1) {
firs = alphabet[i];
break;
}
}
if (firs == "?") {
firs = alphabet[3];
}
ans += firs;
vector<int> possible;
int cnt = 0;
for (int i = 0; i < 4; i++) {
if (alphabet[i] != firs && cnt < 2) {
possible.push_back(i);
cnt++;
}
}
for (int i = 1; i < n; i++) {
bool found = false;
for (int x : possible) {
if (press(ans + alphabet[x]) == i + 1) {
ans += alphabet[x];
found = true;
break;
}
}
if (!found) {
for (int i = 3; i >= 0; i--) {
if (alphabet[i] != firs) {
ans += alphabet[i];
break;
}
}
}
}
return ans;
}
