#include <iostream>
#include <fstream>
#include <vector>
#include <set>
#include <queue>
#include <cmath>
#include <map>
#include <algorithm>
#include <numeric>
#include <stack>
#include <cstring>
#include <bitset>
#include <climits>
#include <valarray>
#include <list>
#include "combo.h"
//#define int long long
#define INF 1000000000
#define endl '\n'
#define mod 1000000007
using namespace std;
vector<string> all;
string ar[4] = {"A", "B", "X", "Y"};
void fills(string cur){
if (cur.size() == 3) all.push_back(cur);
for (int j = 0; j < 4; j++){
if (ar[j][0] == cur[0]) continue;
string temp = cur;
temp += ar[j][0];
fills(temp);
}
}
string guess_sequence(signed n){
if (n == 3){
fills("");
int cur = all.size();
for (int i = 0; i < cur; i++) {
if (press(all[i]) == 3) return all[i];
}
}
string ans;
for (int i = 0; i < n; i++){
for (int j = 0; j < 4; j++) {
if (press(ar[j]) == 1) {
ans += ar[j];
break;
}
}
}
return ans;
}
//signed main(){
// ios_base::sync_with_stdio(false);
// cin.tie(0);
// cout.tie(0);
//
//}
