#include "combo.h"
#include <bits/stdc++.h>
using namespace std;
string guess_sequence(int N) {
string ans;
char f;
int t1 = press("AB");
if (t1) {
int t2 = press("A");
if (t2) f = 'A';
else f = 'B';
} else {
int t2 = press("X");
if (t2) f = 'X';
else f = 'Y';
}
ans += f;
if (N == 1) return ans;
vector<char> a;
string it = "ABXY";
for (auto e : it) if (e != f) a.emplace_back(e);
while (ans.size() != N-1) {
string g1 = ans + a[0];
string g2 = ans + a[1] + a[0];
string g3 = ans + a[1] + a[1];
string g4 = ans + a[1] + a[2];
int t = press(g1 + g2 + g3 + g4);
if (t == ans.size()) ans += a[2];
else if (t == ans.size() + 1) ans += a[0];
else ans += a[1];
}
int t3 = press(ans + a[0]);
int t4 = press(ans + a[1]);
if (t3 == N) return ans + a[0];
else if (t4 == N) return ans + a[1];
else return ans + a[2];
}
