#include "combo.h"
//#include "grader.cpp"
#include <bits/stdc++.h>
using namespace std;
#define ll long long
#define pii pair<int,int>
#define f first
#define s second
#define all(x) x.begin(),x.end()
#define _ ios::sync_with_stdio(0); cin.tie(0); cout.tie(0);
std::string guess_sequence(int n) {
string str;
char st;
vector<char> cs={'X','Y'};
if(press("XY")==0) cs={'A','B'};
st=cs[0];
if(press(string(1,cs[0]))==0) st=cs[1];
vector<char> cand;
for(auto c:{'X','Y','A','B'}){
if(c!=st) cand.push_back(c);
}
str+=st;
for(int i=2;i<n;i++){
string p;
p+=(str+cand[0]+cand[0]);
p+=(str+cand[0]+cand[1]);
p+=(str+cand[0]+cand[2]);
p+=(str+cand[1]);
int res=press(p);
if(res==i+1) str+=cand[0];
else if(res==i) str+=cand[1];
else str+=cand[2];
}
if(n==1) return str;
cs={cand[0],cand[1]};
if(press(str+cand[0]+str+cand[1])==n){
st=cand[0];
if(press(str+cand[0])!=n) st=cand[1];
}
else{
st=cand[2];
}
str+=st;
//cout<<str<<'\n';
return str;
}
