#include "combo.h"
#include <bits/stdc++.h>
using namespace std;
#define ll long long
#define fi first
#define se second
#define sz(a) (long long) a.size()
#define endl '\n'
#define dbg(a) cerr << #a << " = " << a << endl;
#define print(a) for (auto x : a) cerr << x << " "; cerr << endl;
const long long INF = 1e18, MOD = 1e9+7;
string guess_sequence(int n) {
string s = "";
vector<string> a = {"A", "B", "X", "Y"};
int it = 0;
if (press("AB")) {
if (press("A")) it = 0;
else it = 1;
}
else {
if (press("X")) it = 2;
else it = 3;
}
s += a[it];
int x = (it + 1) % 4, y = (it + 2) % 4, z = (it + 3) % 4;
for (int i = 1; i < n - 1; i++) {
int ans = press(s+a[x]+a[y] + s+a[x]+a[z] + s+a[x]+a[x] + s+a[y]);
if (ans == sz(s) + 2) {
s += a[x];
}
else if (ans == sz(s) + 1) {
s += a[y];
}
else {
s += a[z];
}
}
if (press(s + a[x]) == sz(s) + 1) it = x;
else if (press(s + a[y]) == sz(s) + 1) it = y;
else it = z;
s += a[it];
return s;
}
