#include "combo.h"
#include <bits/stdc++.h>
// #define int long long
#define endl "\n"
#define ff first
#define ss second
#define pb push_back
#define all(v) v.begin(), v.end()
using namespace std;
vector <string> v = {"A", "B", "X", "Y"};
string guess_sequence(int n) {
int first = -1;
string p = "";
for(int i = 0; i < v.size() - 1; i++){
if(press(v[i]) > 0){
p += v[i];
first = i;
break;
}
}
if(p.size() == 0)p += v.back(), first = 3;
if(p.size() == n)return p;
vector < string > vv;
for(int i = 0; i < 4; i++){
if(i != first)
vv.push_back(v[i]);
}
v = vv;
while(p.size() < n - 1){
string cur = "";
cur += p;
cur += v[0];
cur += p;
cur += v[1];
cur += v[0];
cur += p;
cur += v[1];
cur += v[2];
cur += p;
cur += v[1];
cur += v[1];
// cout << cur << endl;
int sz = press(cur);
if(sz == p.size()){
p += v[2];
}
else if(sz == p.size() + 1){
p += v[0];
}
else {
p += v[1];
}
}
for(int i = 0; i < 2; i++){
string cur = p + v[i];
if(press(cur) == n){
return cur;
}
}
string ans = p + v.back();
// cout << ans << endl;
return ans;
}
