#define F first
#define S second
#define rep(i,a,b) for(int i=a;!(a==b&&i!=b)&&((i<=b&&b>=a)||(i>=b&&a>=b));i+=(a<=b?1:-1))
#define pb push_back
#define Fbitl __builtin_ffs
#define bit1 __builtin_popcount
//#include <bits/stdc++.h>
#include <iostream>
#include <math.h>
#include <algorithm>
#include <string.h>
#include <vector>
#include <queue>
#include <map>
#include <unordered_map>
#include "combo.h"
using namespace std;
typedef long long ll;
typedef pair<int, int> pii;
typedef pair<ll, ll> pll;
typedef pair<string, string> pss;
typedef vector<int> vi;
typedef vector<vi> vvi;
typedef vector<pii> vii;
typedef vector<ll> vl;
typedef vector<vl> vvl;
string sw = " ABXY";
int howto[6000];
int fidx;
string guess_sequence(int N) {
if (press("ABA")) {
if (press("B")) fidx = 2;
else fidx = 1;
}
else {
if (press("X")) fidx = 3;
else fidx = 4;
}
string res = { sw[fidx] };
string t = res, s = "";
if (N == 1) return res;
for (int j = 1; j < N-1; j++) {
t += ' ';
int c = 0;
for (int i = 1; i <= 4; i++) {
if (i == fidx) continue;
t[j] = sw[i];
if (!c) {
s = t;
howto[j+1] = i;
}
else if (c==1) {
howto[j+2] = i;
for (int i1 = 1; i1 <= 4; i1++) {
if (i1 == fidx) continue;
s += t; s += sw[i1];
}
}
c++;
if (c == 3) {
howto[j] = i;
int a = press(s);
res += sw[howto[a]];
t[j] = sw[howto[a]];
}
}
}
res += ' ';
for (int i = 1; i <= 4; i++) {
if (i == fidx) continue;
if (i == 4 || (fidx == 4 && i == 3)) {
res[N-1] = sw[i];
break;
}
res[N - 1] = sw[i];
if (press(res)==N) return res;
}
return res;
}
