#include "bits/stdc++.h"
#include "combo.h"
using namespace std;
#define ln "\n"
#define dbg(x) cout << #x << " = " << x << ln
#define mp make_pair
#define pb push_back
#define fi first
#define se second
#define inf 2e18
#define fast_cin() \
ios_base::sync_with_stdio(false); \
cin.tie(NULL)
#define out(file) freopen(file, "w", stdout)
#define in(file) freopen(file, "r", stdin)
#define all(x) (x).begin(), (x).end()
#define sz(x) ((int)(x).size())
// #define int long long
int MOD = 1e9 + 7;
string d[4] = {"A", "B", "X", "Y"};
string guess_sequence(int n) {
string ans = "";
if(press("AB") > 0) {
if(press("A") == 1) ans += 'A';
else ans += 'B';
} else {
if(press("X") == 1) ans += 'X';
else ans += 'Y';
}
string fir = ans;
vector<string> vec;
for(int i = 0; i < 4; i++) {
if(d[i] == fir) continue;
vec.pb(d[i]);
}
for(int i = 1; i < n - 1; i++) {
string tmp = ans + vec[0] + vec[1] + ans + vec[0] + vec[0] + ans + vec[0] + vec[2] + ans + vec[1] ;
// cout << tmp << ln;
int cur = press(tmp);
if(cur == sz(ans)) {
ans += vec[2];
} else if(cur == sz(ans) + 1) {
ans += vec[1];
} else {
ans += vec[0];
}
}
if(n == 1) return ans;
string tmp = ans + vec[0];
if(press(tmp) == sz(ans) + 1) {
ans += vec[0];
} else {
tmp = ans + vec[1];
if(press(tmp) == sz(ans) + 1) ans += vec[1];
else ans += vec[2];
}
return ans;
}
// signed main() {
// string a = "";
// a += d[1] + d[2] + d[0];
// string tmp = a + d[0] + a + d[1] + a + d[2] + a + d[3];
// cout << tmp;
// }
