#include "combo.h"
#include <bits/stdc++.h>
using namespace std;
typedef long long ll;
void DBG() { cerr << "]" << endl; }
template<class H, class... T> void DBG(H h, T... t) { cerr << to_string(h); if(sizeof...(t)) cerr << ", "; DBG(t...); }
#define dbg(...) cerr << "[" << #__VA_ARGS__ << "]: [", DBG(__VA_ARGS__)
const int N = 2e5 + 3;
char ELEM[4] = {'A', 'B', 'X', 'Y'};
string guess_sequence(int n) {
string s = "";
for (int i = 1; i <= n; i++) {
for (int d = 0; d < 4; d++) {
string p = s + ELEM[d];
if (press(p) == i) {
s = p; break;
}
}
}
return s;
}
