#include <iostream>
#include <vector>
#include <set>
#include <map>
#include <algorithm>
#include <cmath>
#include <queue>
#include <string>
#include "combo.h"
using namespace std;
typedef long long ll;
/*int press(string p) {
cout << "? " << p << "\n";
int v;
cin >> v;
return v;
}*/
string guess_sequence(int N) {
string moves = "ABXY";
char first = '?';
int k = press("AB");
if (k) {
if (press("A")) first = 'A';
else first = 'B';
}
else {
if (press("X")) first = 'X';
else first = 'Y';
}
moves.erase(moves.begin() + moves.find(first), moves.begin() + moves.find(first) + 1);
string ans = string(1, first);
if (N == 1) return ans;
for (int i = 2; i < N; i++) {
string k = ans;
k.push_back(moves[0]);
k += ans;
k.push_back(moves[1]);
k.push_back(moves[0]);
k += ans;
k.push_back(moves[1]);
k.push_back(moves[1]);
k += ans;
k.push_back(moves[1]);
k.push_back(moves[2]);
int q = press(k);
if (q == i) ans.push_back(moves[0]);
else if (q == i + 1) ans.push_back(moves[1]);
else ans.push_back(moves[2]);
}
string s = ans;
s.push_back(moves[0]);
s += ans;
s.push_back(moves[1]);
if (press(s) == N) {
if (press(ans + string(1, moves[0])) == N) ans.push_back(moves[0]);
else ans.push_back(moves[1]);
}
else ans.push_back(moves[2]);
return ans;
}
/*
int main() {
cout << "! " << guess_sequence(5);
}
*/
