#include "combo.h"
#include <bits/stdc++.h>
using namespace std;
std::string guess_sequence(int N) {
vector<char> op = {'A', 'B', 'X', 'Y'};
// FIND first char with BS
string s = "";
if(press("AB")) {
if (press("A")) s+="A", op.erase(op.begin());
else s += "B", op.erase(op.begin()+1);
} else {
if (press("X")) s+="X", op.erase(op.begin()+2);
else s+="Y", op.erase(op.begin()+3);
}
for (int i = 1; i < N-1; i++) {
int k = press(s+op[0]+s+op[1]+op[0]+s+op[1]+op[1]+s+op[1]+op[2]);
if(k==i) s+= op[2];
else if (k==i+1) s+=op[0];
else s+=op[1];
}
if(press(s+op[0])==N) s+=op[0];
else if (press(s+op[1])==N) s+= op[1];
else s+=op[2];
return s;
}
