#include "combo.h"
#include <bits/stdc++.h>
//#include"grader.cpp"
using namespace std;
std::string guess_sequence(int N) {
std::string p = "";
string s[4]={"A","B","X","Y"};
string first;
for(int i=0;i<4;i++){
p=s[i];
int ok=press(p);
//cout<<ok;
if(ok==1){
first=s[i]; break;
}
}
string ret=first;
//S=first;
//ret+="B";
//cout<<ret<<endl;
int si=N;si--;
int now=2;
while(si){
for(int i=0;i<4;i++){
if(s[i]==first){continue;}
int ok=press(ret+s[i]);
if(ok==now){
ret+=s[i];
now++;
break;
}
}si--;
}
return ret;
}
