#include <bits/stdc++.h>
#include "combo.h"
using namespace std;
using ll = long long;
using vi = vector<long long>;
#define pb emplace_back
std::string guess_sequence(int N) {
char start;
if(press("A"))
start = 'A';
else if (press("B"))
start = 'B';
else if(press("X"))
start = 'C';
else
start = 'Y';
string res;
res += start;
set<char> moves{'A', 'B', 'X', 'Y'};
moves.erase(start);
ll curr = 1;
for(auto x : moves) {
ll gain = press(res + x);
if(gain > curr) {
curr = gain;
res += x;
}
}
for(auto x : moves) {
ll gain = press(res + x);
if(gain > curr) {
curr = gain;
res += x;
}
}
return res;
}
