#include <bits/stdc++.h>
#include "combo.h"
using namespace std;
std::string guess_sequence(int N) {
//first letter
string p = "AB";
char fir;
int tmp1 = press(p);
if(tmp1==0){
int tmp2 = press("X");
if(tmp2==1) fir = 'X';
else fir = 'Y';
}
else{
int tmp2 = press("A");
if(tmp2==1) fir = 'A';
else fir = 'B';
}
set<char> letters;
letters.insert('A');
letters.insert('B');
letters.insert('X');
letters.insert('Y');
letters.erase(fir);
vector<char> v;
for(char i: letters) v.push_back(i);
// for(char i: letters) cout<<i<<" ";
// cout<<"----\n";
//the rest of the letters
string curstr = "";
curstr += fir;
if(N==1) return curstr;
// cout<<curstr<<"!!";
p = "";
for(int i=2; i<N; i++){
string S = "";
S += curstr;
int tmp = 0;
for(char j: letters){
// cout<<j<<" ";
if(tmp==0){
S+=j;
}
else{
S+=curstr;
S+=j;
S+=v[0];
S+=curstr;
S+=j;
S+=v[1];
S+=curstr;
S+=j;
S+=v[2];
break;
}
tmp++;
}
// cout<<"\n"<<S<<"\n";
int tmp3 = press(S);
int sz = curstr.length();
if(tmp3==(sz)){
curstr+=v[2];
}
else if(tmp3==(sz+1)){
curstr+=v[0];
}
else{
curstr+=v[1];
}
// cout<<curstr<<"\n";
}
//last letter
string S1 = "";
S1+=curstr;
S1+=v[0];
int sz = S1.size();
int tmp = press(S1);
if(tmp==sz) curstr+=v[0];
else{
string S = "";
S+=curstr;
S+=v[1];
tmp = press(S);
if(tmp==sz) curstr+=v[1];
else curstr+=v[2];
}
// cout<<curstr<<"\n";
return curstr;
}
