#include <bits/stdc++.h>
#include "combo.h"
#define pb push_back
#define repp(i,x,n) for(int i=x;i<=n;i++)
#define rep(i,x,n) for(int i=x;i>=n;i--)
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";
}
vector<char>v;
char a[4]={'A','B','X','Y'};
repp(i,0,3){
if(s[0]!=a[i]) v.pb(a[i]);
}
while(s.length()!=n-1){
int ah=press(s+v[0]+s+v[1]+v[0]+s+v[1]+v[1]+s+v[1]+v[2]);
if(ah==(int)s.size()) s+=v[2];
else if(ah==(int)s.size()+2) s+=v[1];
else s+=v[0];
}
if(press(s+v[0])==(int)s.size()+1) s+=v[0];
else if(press(s+v[1])==(int)s.size()+1) s+=v[1];
else s+=v[2];
return s;
}
