#include "combo.h"
#include <bits/stdc++.h>
using namespace std;
typedef long long ll;
int ask(int n, string s, char c) {
string query = s;
for (int i = 1; i <= n; ++i) query += c;
return press(query);
}
string guess_sequence(int n) {
string s = "";
if (press("A") == 1) s += "A";
else if (press("B") == 1) s += "B";
else if (press("X") == 1) s += "X";
else s += "Y";
if (n == 1) return s;
vector<char> c;
for (auto ch : {'A', 'B', 'X', 'Y'}) {
if (ch != s[0]) {
c.push_back(ch);
}
}
while (s.size() < n) {
vector<char> c;
for (auto ch : {'A', 'B', 'X', 'Y'}) {
if (ch != s[0] && ch != s.back()) {
c.push_back(ch);
}
}
int len = s.size();
int x = ask(n, s, c[0]);
if (x != len) {
for (int j = 1; j <= x - len; ++j) s += c[0];
} else {
x = ask(n, s, c[1]);
if (x != len) {
for (int j = 1; j <= x - len; ++j) s += c[1];
} else {
x = ask(n, s, c[2]);
for (int j = 1; j <= x - len; ++j) s += c[2];
}
}
}
return s;
}
