#include "combo.h"
#include<bits/stdc++.h>
using namespace std;
#define ll long long
string guess_sequence(int N) {
string s;
// first character
if (press("AB")==1) {
if (press("A")==1) s = "A";
else s = "B";
}
else {
if (press("X")==1) s = "X";
else s = "Y";
}
if (N==1)
return s;
char first = s[0];
// all other characters except the last
char zero, one, two;
if (first=='A')
two = 'B', one = 'X', zero = 'Y';
else if (first=='B')
two = 'A', one = 'X', zero = 'Y';
else if (first=='X')
two = 'A', one = 'B', zero = 'Y';
else
two = 'A', one = 'B', zero = 'X';
string p;
int score;
for (int c=1; c<N-1; c++) {
p = s + two + two + s + two + one + s + two + zero + s + one;
score = press(p);
if (score==c+2)
s += two;
else if (score==c+1)
s += one;
else
s += zero;
}
// last character
if (press(s+two+s+one)==N) {
if (press(s+two)==N)
s += two;
else
s += one;
}
else
s += zero;
return s;
}
