#include "combo.h"
#include "bits/stdc++.h"
#define rep(i, n) for(ll i = 0; i < ll(n); ++i)
#define rep2(i, s, n) for(ll i = ll(s); i < ll(n); ++i)
#define rrep(i, n) for(ll i = ll(n)-1; i >= 0; --i)
#define pb push_back
#define eb emplace_back
#define all(a) a.begin(),a.end()
#define SZ(a) int(a.size())
using namespace std;
using ll = long long;
using P = pair<int, int>;
using vi = vector<int>;
using vvi = vector<vi>;
using vl = vector<ll>;
using vvl = vector<vl>;
using vb = vector<bool>;
using vvb = vector<vb>;
using vp = vector<P>;
using vvp = vector<vp>;
using vs = vector<string>;
string guess_sequence(int n) {
const string S = "ABXY";
string res;
string rem;
{
int a = press("XY") > 0;
int b = press(S.substr(a * 2 + 1, 1)) > 0;
res.pb(S[a * 2 + b]);
rep(i, 4) if (i != a * 2 + b) rem.pb(S[i]);
}
auto f = [&](int i, int j) -> string {
string t = res;
t.pb(rem[i]);
t.pb(rem[j]);
return t;
};
while (SZ(res) < n) {
if (SZ(res) < n - 1) {
int now = press(f(0, 0) + f(0, 1) + f(1, 0));
if (now == SZ(res) + 2) {
now = press(f(0, 0));
if (now == SZ(res) + 2) res = f(0, 0);
else if (now == SZ(res) + 1) res = f(0, 1);
else res = f(1, 0);
} else if (now == SZ(res) + 1) {
now = press(f(1, 1));
if (now == SZ(res) + 2) res = f(1, 1);
else if (now == SZ(res) + 1) res = f(1, 2);
else res = f(0, 2);
} else {
assert(now == SZ(res));
res.pb(rem[2]);
}
} else {
string t = res;
t.pb(rem[0]);
if (press(t) == n) {
res.pb(rem[0]);
} else {
t.pop_back();
t.pb(rem[1]);
res.pb(press(t) == n ? rem[1] : rem[2]);
}
}
}
return res;
}
