#include "combo.h"
#include "bits/stdc++.h"
using namespace std;
#define FOR(i,j,k) for(int i=j;i<k;i++)
const char L[] = "ABXY";
int twoN (const string& s) {
int c = press(s+L[0]+s+L[1]);
int k = 2 * (c <= s.length());
c = press(s+L[k]);
k += (c <= s.length());
return k;
}
string guess_sequence(int N) {
string s;
int a[4];
FOR(i,0,4) { a[i] = i; }
int k = twoN(s);
s += L[k];
swap(a[k], a[3]);
FOR(i,0,N-2) {
string z;
FOR(j,0,3) {
z += s + L[a[0]] + L[a[j]];
}
z += s + L[a[1]];
int cyc = press(z);
if (cyc == i+2) {
s += L[a[1]];
} else if (cyc == i+3) {
s += L[a[0]];
} else {
s += L[a[2]];
}
}
if (N>1) {
int k = twoN(s);
s += L[k];
}
return s;
}
/* 2N bound
FOR(i,0,N) {
int c = press(s+L[0]+s+L[1]);
int k = 2 * (c <= i);
c = press(s+L[k]);
k += (c <= i);
s += L[k];
}
*/
