#include<bits/stdc++.h>
#define rep(i,a,b) for(int i=a;i<b;i++)
#define rrep(i,a,b) for(int i=a;i>=b;i--)
#define pb push_back
#define rl "\n"
#define ll long long
#include "combo.h"
using namespace std;
string guess_sequence(int N)
{
int n=N;
if(n==1)
{
string s="";
s+="A";
int a=press(s);
if(a==1)
{
return s;
}
s="B";
a=press(s);
if(a==1)
return s;
s="X";
a=press(s);
if(a==1)
return s;
s="Y";
return s;
}
string ans="";
string g1="XY",g2="AB";
if(press(g1)==0)swap(g1,g2);
string s1="";
s1+=g1[0];
string s2="";
s2+=g1[1];
string s3="";
char a='A',b='B',x='X',y='Y';
string p1="";
if(press(s1)==1)ans+=s1[0];
else ans+=s2[0];
if(ans[0]==a)swap(a,y);
else if(ans[0]==b)swap(b,y);
else if(ans[0]==x)swap(x,y);
s1=ans+a;
s2=ans+b;
s3=ans+x;
p1=s1+a+s1+b+s1+x+s2;
while((int)(ans.size())!=n-1)
{
int pr=press(p1);
if(pr==(int)(ans.size())+2)
{
ans=s1;
}
else if(pr==(int)(ans.size())+1)
{
ans=s2;
}
else
{
ans=s3;
}
s1=ans+a;
s2=ans+b;
s3=ans+x;
p1=s1+a+s1+b+s1+x+s2;
}
string res="";
res+=ans+a+ans+b;
int pr1=press(res);
if(pr1==n)
{
res=ans+a;
pr1=press(res);
if(pr1==n)
{
ans+=a;
}
else
ans+=b;
return ans;
}
else
{
ans+=x;
return ans;
}
}
