#include "combo.h"
#include <bits/stdc++.h>
using namespace std;
string guess_sequence(int N) {
string p = "";
//get the first letter in 2 steps
if (press("AB") >= 1){
if (press("A") == 1) p += 'A';
else p += 'B';
}else{
if (press("X") == 1) p += 'X';
else p += 'Y';
}
if (N==1) return p;
string pos = "";
string T = "ABXY";
for (int i = 0; i < 4; i++){
if (T[i] == p[0]) continue;
pos += T[i];
}
// pos will contain all characters except p[0]
for (int i = 0; i < N-2; i++){
string test = p+pos[1];
for (int j = 0; j < 3; j++){
test += p+pos[0]+pos[j];
}
int num = press(test);
int len = p.size();
if (num == len + 2) p += pos[0];
if (num == len + 1) p += pos[1];
if (num == len) p += pos[2];
}
// last letter
for (int i = 0; i < 2; i++){
if (press(p+pos[i])==N){
return p+pos[i];
}
}
return p+pos[2];
}
