# include "combo.h"
# include <bits/stdc++.h>
using namespace std;
string guess_sequence( int N ){
string S;
if( press("AB") ){
if( press("A") ){
S = "A";
}
else{
S = "B";
}
}else{
if( press( "X" ) ){
S = "X";
}
else{
S = "Y";
}
}
set < char > st = { 'A', 'B', 'X', 'Y' };
st.erase( S[0] );
vector < char > vc;
for( auto c: st ) vc.push_back( c );
for( int i = 2; i <= N-1; i ++ ){
string p = S + vc[0] + S + vc[1] + vc[0] + S + vc[1] + vc[1]+ S + vc[1] + vc[2];
int x = press( p );
if( x == i ){
S += vc[0];
}
else if( x == i+1 ){
S += vc[1];
}
else{
S += vc[2];
}
}
if( press( S+vc[0] ) == N ){
S += vc[0];
}
else if( press( S+vc[1] ) == N ){
S += vc[1];
}
else{
S += vc[2];
}
return S;
}
