#include<bits/stdc++.h>
#include <combo.h>
using namespace std;
#define rc(x) return cout<<x<<endl,0
#define pb push_back
#define dbg(x) cout << #x << '=' << x << '\n';
#define ll long long
#define sz size()
#define x first
#define y second
#define pi pair <int, int>
#define pii pair <int, pi>
#define vi vector <int>
const ll mod = 1e9 + 7;
string guess_sequence(int n){
string s="";
char use[4];
vector <char> ch={'A', 'B', 'X', 'Y'};
if(press("AB")){
if(press("A")){
s+='A';
}
else{
s+='B';
}
}
else{
if(press("X")){
s+='X';
}
else{
s+='Y';
}
}
if(n==1) return s;
// cout<<s<<endl;
int q=0;
for(int i=0; i<=3; i++){
if(ch[i]!=s[0]) use[q]=ch[i], q++;
}
//for(string i: use) cout<<"x"<<i<<endl;
string xd="";
for(int i=1; i<n-1; i++){
xd=(s+use[0]+s+use[1]+use[0]+s+use[1]+use[1]+s+use[1]+use[2]);
// cout<<s<<" "<<xd;//<<endl;
q=press(xd); //cout<<" "<<q<<endl;
if(q==i+2) s+=use[1];
else if(q==i+1) s+=use[0];
else s+=use[2];
//cout<<s<<endl;
}//cout<<s<<endl;
if(press(s+use[0])==n){
return s+use[0];
}
if(press(s+use[1])==n){
return s+use[1];
}
return s+use[2];
}
