#include <bits/stdc++.h>
#include <combo.h>
using namespace std;
// #define int long long
#define pint pair < int , int >
#define ll long long
#define ff first
#define ss second
#define fast ios_base::sync_with_stdio(NULL); cin.tie(NULL)
const int inf = 1e9 + 9;
const int mxn = 2e5 + 2;
const int mod = 1e9 + 7;
// int press(string p) {}
string guess_sequence(int n) {
int t1 = press("AB");
int t2 = press("BX");
char a , b , c , z;
if (t1 == 0) {
a = 'A';
b = 'B';
if (t2 == 0) {
z = 'Y';
c = 'X';
} else {
z = 'X';
c = 'Y';
}
} else {
c = 'Y';
if (t2 == 0) {
a = 'B';
b = 'X';
z = 'A';
} else {
a = 'A';
b = 'X';
z = 'B';
}
}
string str;
str += z;
int prev = 1;
for (int i = 0; i < n-2; i++) {
int t = press(str + a + str + b + a + str + b + b + str + b + c);
if (t - prev == 0) str += c;
if (t - prev == 1) str += a;
if (t - prev == 2) str += b;
prev = t;
}
int t = press(str + a);
if (t == n) str += a;
if (t == n-1) {
if (press(str + b) == n) str += b;
else str += c;
}
return str;
}
