#include<bits/stdc++.h>
//#include "insects.h"
#define f first
#define s second
#define pb push_back
#define pii pair<int,int>
#define ll long long
using namespace std;
int press(std::string p);
std::string guess_sequence(int N){
std::string ans="";
char s[4];
if(press("A")==1)ans="A",s[0]='A',s[1]='B',s[2]='X',s[3]='Y';
else if(press("B")==1)ans="B",s[0]='B',s[1]='A',s[2]='X',s[3]='Y';
else if(press("X")==1)ans="X",s[0]='X',s[1]='B',s[2]='A',s[3]='Y';
else ans="Y",s[0]='Y',s[1]='B',s[2]='X',s[3]='A';
for(int i=2;i<=N-1;i++){
std::string now1 = ans;now1+=s[1];
std::string now2 = ans;now2+=s[2];now2+=s[1];
std::string now3 = ans;now3+=s[2];now3+=s[2];
std::string now4 = ans;now4+=s[2];now4+=s[3];
std::string tt = now1+now2+now3+now4;
int x = press(tt);
if(x==i-1)ans = ans+s[3];
else if(x==i)ans = ans+s[1];
else ans = ans+s[2];
}if(press(ans+s[1])==N)return ans+s[1];
if(press(ans+s[2])==N)return ans+s[2];
else return ans+s[3];
}
