#include <climits>
#include <iostream>
#include <algorithm>
#include <cmath>
#include <deque>
#include <map>
#include <numeric>
#include <queue>
#include <set>
#include <stack>
#include <string>
#include <unordered_set>
#include <unordered_map>
#include <utility>
#include <vector>
#include "combo.h"
using namespace std;
using ll = long long;
string guess_sequence(int N) {
string cur;
char letters[] {'A', 'B', 'X', 'Y'};
for (int i = 0; i < N; i++) {
int t_i = 0;
for (; ; t_i++) {
if (press(cur + letters[t_i]) == i+1) {
break;
}
}
cur += letters[t_i];
}
return cur;
}
