#include "combo.h"
#include <bits/stdc++.h>
using namespace std;
vector<char> cand = {'A', 'B', 'X', 'Y'};
vector<char> V;
std::string guess_sequence(int N) {
std::string S = "";
if(press("AB")){
if(press("A")) S = "A";
else S = "B";
}
else{
if(press("X")) S = "X";
else S = "Y";
}
if(N == 1) return S;
for(auto v : cand){
if(v == S[0]) continue;
else V.push_back(v);
}
// for(auto v : V) cout << v << endl;
while((int) S.size() < N-1){
string query = S + V[0] + S + V[1] + V[0] + S + V[1] + V[1] + S + V[1] + V[2]; // SXSYBSYXSYY
int ret = press(query);
if(ret == (int) S.size()) S += V[2];
else if(ret == (int) S.size() + 1) S += V[0];
else S += V[1];
}
if(press(S + V[0]) == N){
S += V[0];
}
else if(press(S + V[1]) == N){
S += V[1];
}
// else return S + V[2];
else S += V[2];
cout << S << endl;
return S;
}
