#include "combo.h"
using namespace std;
using ll = long long;
using ld = long double;
const int N = 3e5 +2;
const int base = 31;
const int mod = 1e9 +7;
int a[4], k;
string c[4] = {"A", "B", "X", "Y"};
string guess_sequence(int n)
{
string res;
if(!n)return res;
if(press(c[0]+c[1]))
{
if(press(c[1]))swap(c[0], c[1]);
}
else if(press(c[2]))swap(c[0], c[2]);
else swap(c[0], c[3]);
res = c[0];
if(n == 1)return res;
for(int i = 2; i < n; i ++)
{
k = press(res+c[2]+res+c[3]+c[1]+res+c[3]+c[2]+res+c[3]+c[3]);
if(k == i-1)res += c[1];
else if(k == i)res += c[2];
else res += c[3];
}
for(int i = 1; i < 4; i ++)
{
if(press(res+c[i]) == n)
{
res += c[i];
break;
}
}
return res;
}
