# include <bits/stdc++.h>
using namespace std;
# define ll long long
# define ld long double
# define pb push_back
# define pob pop_back
# define mp make_pair
# define fi first
# define se second
# define all(x) x.begin(),x.end()
# define ts to_string
# define ti(a) atoi(a.c_str())
# define NumAfterDecimalP(x) cout<<setprecision(x)<<fixed
const ld pi = 2*acos(0.0);
const ll inf = LLONG_MAX;
const ll mod = 1e9+7;
#include "combo.h"
std::string guess_sequence(int N) {
string ans="";
for(int i=1; i<=N; i++){
string temp1=ans,temp2=ans,temp3=ans,temp4=ans;
temp1+='A';
temp2+='B';
temp3+='X';
temp4+='Y';
ll o1=press(temp1);
if(o1==i){
ans=temp1;
continue;
}
ll o2=press(temp2);
if(o2==i){
ans=temp2;
continue;
}
ll o3=press(temp3);
if(o3==i){
ans=temp3;
continue;
}
else{
ans=temp4;
continue;
}
}
return ans;
}
