#include<bits/stdc++.h>
using namespace std;
#define ll long long
#define pb push_back
#define ff first
#define ss second
#define _ << " " <<
#define yes cout<<"YES\n"
#define no cout<<"NO\n"
#define ull unsigned long long
#define lll __int128
#define all(x) x.begin(),x.end()
#define rall(x) x.rbegin(),x.rend()
#define BlueCrowner ios_base::sync_with_stdio(0); cin.tie(0); cout.tie(0);
#define FOR(i, a, b) for (ll i = (a); i < (b); i++)
#define FORD(i, a, b) for (ll i = (a); i >= (b); i--)
#include "combo.h"
string guess_sequence(int n) {
int a = press("AB");
int b = press("XB");
string s;
char c;
if(a == 1 && b == 1) c = 'B';
else if(a >= 1) c = 'A';
else if(b >= 1) c = 'X';
if(a == 0 && b == 0) c = 'Y';
s.pb(c);
char let[] = {'A', 'B', 'X', 'Y'};
vector<char> l;
FOR(j, 0, 4) if(let[j] != c) l.pb(let[j]);
FOR(i, 1, n - 1) {
string cur = s + l[0] + l[0] + s + l[0] + l[1] + s + l[0] + l[2] + s + l[1];
int x = press(cur);
if(x == i + 2) s.pb(l[0]);
if(x == i + 1) s.pb(l[1]);
if(x == i) s.pb(l[2]);
if(i == n - 2) {
int x = press(s + l[0]);
if(x == n) {
s.pb(l[0]);
break;
}
x = press(s + l[1]);
if(x == n) {
s.pb(l[1]);
break;
}
s.pb(l[2]);
break;
}
}
return s;
}
