#include <iostream>
#include <fstream>
#include <iomanip>
#include <algorithm>
#include <functional>
#include <numeric>
#include <cstring>
#include <string>
#include <cmath>
#include <vector>
#include <queue>
#include <stack>
#include <set>
#include <map>
using namespace std;
#define ll long long
#define ull unsigned long long
#define f first
#define s second
#define PF push_front
#define PB push_back
#define MP make_pair
#define max(a, b) ((a > b)? a : b)
#define min(a, b) ((a < b)? a : b)
#define max3(a, b, c) max(max(a, b), c)
#define min3(a, b, c) min(min(a, b), c)
const int N = 2e3 + 5;
const int M = 1e9 + 7;
const int inf = 0x3f3f3f3f;
const ll int INF = 1e18;
int press(string s);
string guess_sequence(int n){
string str = "";
char c[4] = {'A', 'B', 'X', 'Y'};
// Get first char
int temp = press("AB");
if(temp) str = press("A")? 'A' : 'B';
else str = press("X")? 'X' : 'Y';
// 1 Press OP
int val[3];
for(int i = 0, ind = 0; i < 4; i++){
if(c[i] == str[0]) continue;
val[ind++] = i;
}
for(int i = 1; i < n-1; i++){
int type = 0;
string query = "";
for(int j = 0; j < 4; j++){
if(c[j] == str[0]) continue;
if(!type){
for(int k = 0; k < 4; k++){
if(c[k] == str[0]) continue;
query += (string)(str + c[j] + c[k]);
}
}else if(type == 1){
query += (string)(str + c[j] + str[0]);
}
type++;
}
temp = press(query);
str += c[val[i + 2 - temp]];
}
// Get last char
if(n > 1){
string query = str + 'A' + str + 'B';
temp = press(query);
if(temp == n) str += (press(str + 'A') == n)? 'A' : 'B';
else str += (press(str + 'X') == n)? 'X' : 'Y';
}
return str;
}
