#include "combo.h"
#include <bits/stdc++.h>
using namespace std;
string guess_sequence(int N) {
string chs = "ABXY", ans;
if(press("AB")) {
if(press("A")) ans.push_back('A');
else ans.push_back('B');
}
else if(press("X")) ans.push_back('X');
else ans.push_back('Y');
if(N==1) return ans;
for(int i=0; i<4; i++)
if(chs[i]==ans[0]) {
swap(chs[i], chs.back());
break;
}
chs.pop_back();
for(int i=1; i+1<N; i++) {
string ask = ans;
ask.push_back(chs[0]);
ask += ans;
ask.push_back(chs[1]);
ask.push_back(chs[0]);
ask += ans;
ask.push_back(chs[1]);
ask.push_back(chs[1]);
ask += ans;
ask.push_back(chs[1]);
ask.push_back(chs[2]);
int res = press(ask);
if(res==i) ans.push_back(chs[2]);
else if(res==i+1) ans.push_back(chs[0]);
else ans.push_back(chs[1]);
}
ans.push_back(chs[0]);
if(press(ans)==N) return ans;
ans.back() = chs[1];
if(press(ans)==N) return ans;
ans.back() = chs[2];
return ans;
}
