#include "combo.h"
#include <bits/stdc++.h>
using namespace std;
#define TL ios::sync_with_stdio(0),cin.tie(0),cout.tie(0);
#define rall(s) s.rbegin(),s.rend()
#define all(s) s.begin(),s.end()
#define pb push_back
#define se second
#define fi first
#define ll long long
#define ld long double
#define YES cout<<"YES\n"
#define Yes cout<<"Yes\n"
#define yes cout<<"yes\n"
#define NO cout<<"NO\n"
#define No cout<<"No\n"
#define no cout<<"no\n"
//const int N = 5e5 + 9 , mod = 1e9 + 7;
//ll a[N] , b[N] , dp[N] , c[N] , d[N];
//int press(string a){}
std::string guess_sequence(int n){
vector<string>v = {"A" , "B" , "X", "Y"};
if(n == 1){
for(auto to : v)
if(to == "Y" || press(to))
return to;
}
string b;
if(press("AB")){
b = (press("A") ? "A" : "B");
}else{
b = (press("X") ? "X" : "Y");
}
vector<string>vc;
for(auto to : v)
if(to != b)
vc.pb(to);
for(int i = 1; i < n - 1; i++){
string a = b + vc[0] + vc[0] + b + vc[0] + vc[1] + b + vc[0] + vc[2] + b + vc[1];
int k = press(a);
if(k == i + 2)
b += vc[0];
else if(k == i + 1)
b += vc[1];
else
b += vc[2];
}
if(press(b + vc[0] + b + vc[1]) == n)
b += ((press(b + vc[0]) == n) ? vc[0] : vc[1]);
else
b += vc[2];
return b;
}
/*
int main(){
#ifndef ONLINE_JUDGE
freopen("input.txt", "r", stdin);
freopen("output.txt", "w", stdout);
#endif
guess_sequence(2);
}*/
// Author : حسن
