#include <combo.h>
#include <iostream>
using namespace std;
#define rep(i, a, b) for (auto i = (a); i < (b); ++i)
char first = 'A';
string wlog(string s) {
for (char &c : s)
if (c == 'A') c = first;
else if (c == first) c = 'A';
return s;
}
int ask(const string &p) { return press(wlog(p)); }
string guess_sequence(int n) {
if (ask("AB"))
first = ask("A") ? 'A' : 'B';
else
first = ask("X") ? 'X' : 'Y';
string s{'A'};
if (n > 1) {
rep(i, 1, n - 1) {
int cnt = ask(s + "BB" + s + "BX" + s + "BY" + s + "X");
if (cnt == i + 0) s += "Y";
if (cnt == i + 1) s += "X";
if (cnt == i + 2) s += "B";
}
if (ask(s + "B" + s + "X") == n)
s += ask(s + "B") == n ? "B" : "X";
else s += "Y";
}
return wlog(s);
}
