#include "combo.h"
#include <bits/stdc++.h>
#define pb push_back
using namespace std;
char guess_first_char(){
if(press("AB")){
if(press("A"))return 'A';
else return 'B';
} else {
if(press("X"))return 'X';
else return 'Y';
}
}
std::string guess_sequence(int N) {
vector<char> v;
char c = guess_first_char();
if(c!='A')v.pb('A');
if(c!='B')v.pb('B');
if(c!='X')v.pb('X');
if(c!='Y')v.pb('Y');
string ans;
ans.pb(c);
N--;
while(N >= 2){
string q;
q += ans;
q += v[0];
q += ans;
q += v[1];
q += v[0];
q += ans;
q += v[1];
q += v[1];
q += ans;
q += v[1];
q += v[2];
int x=press(q);
if(x == ans.size())ans.pb(v[2]);
else if(x == (ans.size()+1))ans.pb(v[0]);
else ans.pb(v[1]);
N--;
}
if(N == 1){
if(press(ans + v[0])!=ans.size())return ans+v[0];
if(press(ans + v[1])!=ans.size())return ans+v[1];
return ans+v[2];
}
return ans;
}
