#include <bits/stdc++.h>
using namespace std;
#ifdef wambule
int press(string) {
return 0;
}
#else
int press(string);
#endif
string s = "";
int ask(vector<string> v) {
assert(v.size() < 5);
string c = "";
for(string t : v) {
c += s + t;
}
return press(c) - s.size();
}
string guess_sequence(int n) {
string c[] = {"X", "Y", "A", "B"};
if(!ask({c[0], c[1]})) {
swap(c[0], c[2]);
swap(c[1], c[3]);
}
if(!ask({c[0]})) swap(c[0], c[1]);
s = c[0];
swap(c[0], c[3]);
for(int i = 1; i < n; ++i) {
int x = ask({c[0] + c[0], c[0] + c[1], c[0] + c[2], c[1]});
if(x == 2) {
s += c[0];
} else if(x == 1) {
s += c[1];
} else {
s += c[2];
}
}
if(ask({c[0]})) s += c[0];
else if(ask({c[1]})) s += c[1];
else s += c[2];
return s;
}
#ifdef wambule
int main() {
ios::sync_with_stdio(0);
cin.tie(0);
return 0;
}
#endif
