#include "combo.h"
#include<bits/stdc++.h>
using namespace std;
#define pb push_back
#define ll long long
string guess_sequence(int N) {
vector<char> a = {'A', 'B', 'X', 'Y'};
string s;
if(press("AB")){
if(press("A")) s = "A";
else s = "B";
}
else if(press("X"))s="X";
else s = "Y";
ll cnt = 1;
vector<char> v;
for(int i = 0; i < 4; ++i){
if(a[i] != s[0]){
v.pb(a[i]);
}
}
while(1){
cnt++;
if(cnt==N){
if(press(s + v[0]) == N){
s += v[0];
}
else if(press(s + v[1]) == N){
s += v[1];
}
else s += v[2];
break;
}
else{
int count = press(s + v[0] + s + v[1] + v[0] + s + v[1] + v[2] + s + v[1] + v[1]);
if(count == cnt ){
s += v[0];
}
else if(count == cnt + 1){
s += v[1];
}
else s += v[2];
}
}
return s;
}
