#include <bits/stdc++.h>
#include "combo.h"
using namespace std;
string cand = "ABXY";
string s;
string solve_1() {
string S;
string a = "A", b = "B", x = "X";
int aa = press(a), bb = press(b), xx = press(x);
if (aa)
S = a;
else if (bb)
S = b;
else if (xx)
S = x;
else
S = "Y";
return S;
}
string guess(string prefix)
{
string ret = prefix;
ret += s[0];
for (int i = 0; i < 3; i++)
{
ret += prefix;
ret += s[1];
ret += s[i];
}
return ret;
}
string guess_sequence(int N)
{
if(N == 1) return solve_1();
string S;
int a = press({"AB"});
if(a >= 1) {
int b = press("AA");
if(b) S = "A";
else S = "B";
}
else {
int b = press("XX");
if(b) S = "X";
else S = "Y";
}
char c = S[0];
for (int i = 0; i < 4; i++)
{
if (cand[i] != c)
s += cand[i];
}
for(int i = 0; i < N - 2; i++) {
string now = guess(S);
int v = press(now) - S.length();
if(v == 2) S += s[1];
else if(v == 1) S += s[0];
else S += s[2];
}
int idx = 2;
for(int i = 0; i < 1; i++) {
for(int j = 0; j < 2; j++) {
string now = S + s[j];
int v = press(now);
if(v > S.length()) {
idx = j;
break;
}
}
}
S += s[idx];
return S;
}
