#include <bits/stdc++.h>
#include "combo.h"
using namespace std;
typedef long long ll;
typedef map<ll, ll> mp;
typedef pair<ll, ll> pll;
typedef queue<ll> qi;
typedef vector<ll> vi;
typedef vector<bool> vb;
typedef vector<vi> vvi;
typedef vector<pll> vpl;
typedef vector<string> vs;
#define YES cout << "YES\n"
#define Yes cout << "Yes\n"
#define NO cout << "NO\n"
#define No cout << "No\n"
#define F first
#define S second
#define pb push_back
#define all(x) begin(x), end(x)
ll go() {
ll q = press("AB");
if (q >= 1) {
q = press("A");
if (q == 1) return 0;
else return 1;
} else {
q = press("X");
if (q == 1) return 2;
else return 3;
}
}
string guess_sequence(int N) {
string ans = "";
vector<char> idx = {'A', 'B', 'X', 'Y'};
ll a = go();
ans += idx[a];
for (int i = 1; i < N; i++) {
string test = ans;
if (ans[0] == 'A') {
test += "B" + ans + "X" + ans + "Y";
} else if (ans[0] == 'B') {
test += "A" + ans + "X" + ans + "Y";
} else if (ans[0] == 'X') {
test += "A" + ans + "B" + ans + "Y";
} else {
test += "A" + ans + "B" + ans + "X";
}
ll k = press(test);
if (i == N - 1) {
if (k == i) ans += (ans[0] == 'A' ? 'Y' : 'X');
else if (k == i + 1) ans += (ans[0] == 'A' ? 'B' : 'A');
else ans += (ans[0] == 'A' ? 'X' : 'B');
} else {
if (k == i + 1) ans += (ans[0] == 'A' ? 'B' : 'A');
else if (k == i + 2) ans += (ans[0] == 'A' ? 'X' : 'B');
else ans += (ans[0] == 'A' ? 'Y' : 'X');
}
}
return ans;
}
