#include "combo.h"
#include <bits/stdc++.h>
#include <ext/pb_ds/assoc_container.hpp>
#include <ext/pb_ds/tree_policy.hpp>
using namespace std;
using namespace __gnu_pbds;
#define ll long long
#define ld long double
#define pb push_back
#define all(x) (x).begin(), (x).end()
#define SZ(x) (int)(x).size()
template <typename T> using ord_set = tree <T, null_type, less <T>, rb_tree_tag, tree_order_statistics_node_update>;
mt19937 rng(chrono::steady_clock::now().time_since_epoch().count());
string guess_sequence(int N) {
char c;
if (press("AB") == 0) {
if (press("X")) c = 'X';
else c = 'Y';
} else {
if (press("A")) c = 'A';
else c = 'B';
}
//2
vector <char> v;
for (char i : "ABXY")
if (i != c) v.pb(i);
int cur = 1;
string res = "", query;
res.pb(c);
while (cur < N - 1) {
query = (res + v[0]) + (res + v[1] + v[0]) + (res + v[1] + v[1]) + (res + v[1] + v[2]);
int coins = press(query);
if (coins == cur) res += v[2];
else {
if (coins == cur + 1) res += v[0];
else res += v[1];
}
cur++;
}
//n-2
if (cur < N) {
query = (res + v[0]) + (res + v[1]);
int coins = press(query);
if (coins == cur) res += v[2];
else {
query = (res + v[0]);
if (press(query) == cur + 1) res += v[0];
else res += v[1];
}
}
//2
return res;
}
