#include<iostream>
#include<stack>
#include<map>
#include<vector>
#include<string>
#include<unordered_map>
#include <queue>
#include<cstring>
#include<limits.h>
#include<cmath>
#include<set>
#include<algorithm>
#include<bitset>
#include "combo.h"
using namespace std;
#define ll long long
#define f first
#define endl "\n"
#define s second
#define pii pair<int,int>
#define ppii pair<int,pii>
#define pb push_back
#define p push
#define all(x) x.begin(),x.end()
#define rall(x) x.rbegin(),x.rend()
#define F(n) for(int i=0;i<n;i++)
#define lb lower_bound
#define ub upper_bound
#define fastio ios::sync_with_stdio(false);cin.tie(NULL);
using namespace std;
string guess_sequence(int N){
string v[4]={"A","B","X","Y"};
string op="",ans="",tmp;
if(press("AB")){
if(press("A"))ans="A";
else ans="B";
}
else if(press("x"))ans="X";
else ans="Y";
if(N==1)return ans;
for(int i=0;i<4;i++)if(v[i]!=ans)op+=v[i];
for(int i=1;i<N-1;i++){
string a=ans+op[0]+op[1]+ans+op[0]+op[2]+ans+op[0]+op[0]+ans+op[1];
int b=press(a);
if(b==1)ans+=op[1];
else if(b==2)ans+=op[0];
else ans+=op[2];
}
for(int i=0;i<3;i++){
string v=ans+op[i];
if(i==2)ans=v;
else if(press(v)==N)ans=v;
}
return ans;
}
