#include "combo.h"
#include <bits/stdc++.h>
using namespace std;
string guess_sequence(int n) {
string ans;
if (press ("AB"))
if (press ("A"))ans += 'A';
else ans += 'B';
else if (press ("X"))ans += 'X';
else ans += 'Y';
vector <char> v, I = {'X', 'Y', 'A', 'B'};
for (int i = 0; i < 4; i ++)if (I [i] != ans [0]) v.push_back (I [i]);
for (int i = 2; i < n; i ++){
int val = press (ans + v [0] + ans + v [1] + v [0] + ans + v [1] + v [1] + ans + v [1] + v [2]);
if (val == (int)ans.size ())
ans.push_back (v [2]);
else if (val == (int)ans.size () + 1)
ans.push_back (v [0]);
else ans.push_back (v [1]);
}
if(n != 1) {
if (press (ans + v [0]) == n) ans += v [0];
else if (press (ans + v [1]) == n) ans += v [1];
else ans += v [2];
}
return ans;
}
