#include <iostream>
#include <string>
#include <unordered_map>
#include <cstring>
#include <chrono>
#include <vector>
#include <map>
#include <random>
#include <set>
#include <algorithm>
#include <math.h>
#include <cstdio>
#include <stdio.h>
#include <assert.h>
#include <queue>
#include <bitset>
#include <cstdlib>
#include <deque>
#include <cassert>
#include <stack>
#include "combo.h"
using namespace std;
string guess_sequence(int n) {
char lol[] = {'A', 'B', 'X', 'Y'};
int taken = 0;
while(press("" + lol[taken])==0) taken++;
string s = "" + lol[taken];
for(int i = 1;i<n;i++){
for(int j = 0;j<4;j++){
if(j==taken) continue;
int rn = press(s + lol[j]);
if(rn==(i+1)){
s = s+lol[j];
j = 5;
}
}
}
return s;
}
