#include "combo.h"
#include <bits/stdc++.h>
using namespace std;
#define debug(x) cerr << #x << ": " << x << endl;
#define sep ' '
int n;
string TC[4] = {"A", "B", "X", "Y"};
inline int tpress(string s) {
//cerr << "press: " << s << endl;
return press(s);
}
string guess_sequence(int N_) {
int n = N_;
string ans = TC[3];
if (press(TC[0] + TC[1])) {
if (press(TC[0])) ans = TC[0];
else ans = TC[1];
} else if (press(TC[2])) ans = TC[2];
vector<string> C;
for (int i = 0; i < 4; i++)
if (TC[i] != ans)
C.push_back(TC[i]);
if (n == 1) return ans;
for (int j = 0; j < n - 2; j++) {
string tans = ans + C[0] + ans + C[1] + C[0] + ans + C[1] + C[1] + ans + C[1] + C[2];
int score = tpress(tans);
if (score == j + 1) ans += C[2];
else if (score == j + 2) ans += C[0];
else ans += C[1];
}
for (int i = 0; i < 2; i++)
if (tpress(ans + C[i]) == n)
return ans + C[i];
return ans + C[2];
}
