#include "combo.h"
#include <bits/stdc++.h>
using namespace std;
mt19937_64 rng(chrono::steady_clock::now().time_since_epoch().count());
#define Jungle "IOI18_combo"
#define getbit(x, i) (((x) >> (i)) & 1)
#define MASK(i) (1 << (i))
#define cntbit __builtin_popcount
template <typename t>
void chkmin(t &a, t b)
{
if (a > b) a = b;
}
template <typename t>
void chkmax(t &a, t b)
{
if (a < b) a = b;
}
string guess_sequence(int N)
{
string ans;
if (press("AB")) {
if (press("A")) ans = "A";
else ans = "B";
} else {
if (press("X")) ans = "X";
else ans = "Y";
}
vector<char> rem;
for (char c : {'A','B','X','Y'})
if (c != ans[0]) rem.push_back(c);
char b = rem[0], x = rem[1], y = rem[2];
for (int i = 1; i < N-1; i++) {
string q;
q.reserve(ans.size()*4+10);
q += ans;
q.push_back(b);
q += ans;
q.push_back(x); q.push_back(b);
q += ans;
q.push_back(x); q.push_back(x);
q += ans;
q.push_back(x); q.push_back(y);
int res = press(q);
if (res == (int)ans.size()+1)
ans.push_back(b);
else if (res == (int)ans.size()+2)
ans.push_back(x);
else
ans.push_back(y);
}
for (char c : {b,x,y})
if (press(ans + c) == N) {
ans.push_back(c);
break;
}
return ans;
}
