#include<bits/stdc++.h>
#include "combo.h"
using namespace std;
string guess_sequence(int N){
string ans = "";
char A, B, C, D;
set<int> st;
st.insert('A'), st.insert('B'), st.insert('X'), st.insert('Y');
if(press("AB")){
if(press("A")) A = 'A';
else A = 'B';
}
else{
if(press("X")) A = 'X';
else A = 'Y';
}
ans+=A;
st.erase(A);
auto it = st.begin();
B = *it, it++, C = *it, it++, D = *it;
for(int i = 1; i < N-1; i++){
string aux="";
aux+=ans, aux+=B;
aux+=ans, aux+=C, aux+=B;
aux+=ans, aux+=C, aux+=C;
aux+=ans, aux+=C, aux+=D;
int prs = press(aux) - i;
if(prs==0)
ans+=D;
else if(prs==1)
ans+=B;
else if(prs==2)
ans+=C;
}
string aux = "";
aux+=ans, aux+=B;
if(press(aux)==N) ans+=B;
else{
aux.pop_back();
aux+=C;
if(press(aux)==N) ans+=C;
else ans+=D;
}
return ans;
}
