#include "combo.h"
#include <bits/stdc++.h>
using namespace std;
using ll = long long;
#define fi first
#define se second
typedef pair<int,int> pi;
void debug_out() {cerr<<endl;}
template <typename Head, typename... Tail>
void debug_out(Head _H, Tail... _T) {cerr<<" "<<to_string(_H);debug_out(_T...);}
#define debug(...) cerr<<"["<<#__VA_ARGS__<<"]:",debug_out(__VA_ARGS__)
string ans;
string ch = "ABXY";
char rem[4];
int id;
string guess_sequence(int n) {
int f = press("AB");
if (f) {
if (press("A")) ans += "A";
else ans += "B";
} else {
if (press("X")) ans += "X";
else ans += "Y";
}
for (int i = 0; i < 4; ++i) {
if (ch[i] != ans[0]) {
rem[++id] = ch[i];
}
}
rem[0] = rem[id];
if (n == 1) return ans;
if (n == 2) goto last;
for (int i = 2; i < n; ++i) {
string guess = "";
int cnt = 0;
for (int j = 0; j < 4; ++j) {
if (ans[0] == ch[j]) continue;
++cnt;
if (cnt == 1) {
guess += ans + ch[j];
} else {
for (int k = 0; k < 4; ++k) {
if (ans[0] == ch[k]) continue;
guess += ans + ch[j] + ch[k];
}
break;
}
}
int res = press(guess) - (int)ans.size();
ans += rem[res];
}
last:
for (int i = 0; i < 2; ++i) {
string guess = ans + rem[i];
if (press(guess) == n) return guess;
}
ans += rem[2];
return ans;
}
