//
// Created by adavy on 2/11/2023.
//
#include <bits/stdc++.h>
using namespace std;
using ll = long long;
using ld = long double;
using db = double;
using str = string; // yay python!
using ii = pair<int,int>;
using pl = pair<ll,ll>;
using pd = pair<db,db>;
using vi = vector<int>;
using vb = vector<bool>;
using vl = vector<ll>;
using vd = vector<db>;
using vs = vector<str>;
using vii = vector<ii>;
using vpl = vector<pl>;
using vpd = vector<pd>;
#define tcT template<class T
#define tcTU tcT, class U
tcT> using V = vector<T>;
tcT, size_t SZ> using AR = array<T,SZ>;
tcT> using PR = pair<T,T>;
// pairs
#define mp make_pair
#define f first
#define s second
#define FOR(i,a,b) for (int i = (a); i < (b); ++i)
#define F0R(i,a) FOR(i,0,a)
#define ROF(i,a,b) for (int i = (b)-1; i >= (a); --i)
#define R0F(i,a) ROF(i,0,a)
#define trav(a,x) for (auto& a: x)
#define len(x) int((x).size())
#define bg(x) begin(x)
#define all(x) bg(x), end(x)
#define rall(x) rbegin(x), rend(x)
#define sor(x) sort(all(x))
#define rsz resize
#define ins insert
#define ft front()
#define bk back()
#define pb push_back
#define eb emplace_back
#define pf push_front
const int MOD = 1e9+7; // 998244353;
const int MX = 2e5+5;
const ll INF = 1e18; // not too close to LLONG_MAX
const ld PI = acos((ld)-1);
const int dx[4] = {1,0,-1,0}, dy[4] = {0,1,0,-1}; // for every grid problem!!
#include <cstdio>
#include <cstdlib>
#include <algorithm>
#include <string>
#include "combo.h"
// ABXY
std::string guess_sequence(int N) {
std::string cur = "";
// get the first letter
char FL = ' ';
bool isAB = (press("AB") > 0);
if (isAB){
bool isA = (press("A") > 0);
if (isA) FL = 'A'; else FL = 'B';
}
else {
bool isX = (press("X") > 0);
if (isX) FL = 'X'; else FL = 'Y';
}
vector<char> lets = {'A','B','X','Y'};
vector<char> ml;
trav(i, lets) {
if (i!=FL) ml.pb(i);
}
cur.pb(FL);
F0R(i, N-2){
int cns = press(cur+ml[0]+cur+ml[1]+ml[0]+cur+ml[1]+ml[1]+cur+ml[1]+ml[2]);
if (cns==cur.size()+2) cur.pb(ml[1]);
else if (cns==cur.size()+1) cur.pb(ml[0]);
else cur.pb(ml[2]);
}
if (press(cur + ml[0])==N) cur += ml[0];
else if (press(cur + ml[1])==N) cur += ml[1];
else cur += ml[2];
return cur;
}
