//OPTIMIZATIONS
#pragma GCC optimize("O3")
//(UNCOMMENT WHEN HAVING LOTS OF RECURSIONS)
//#pragma comment(linker, "/stack:200000000")
//(UNCOMMENT WHEN NEEDED)
//#pragma GCC optimize("Ofast,unroll-loops,no-stack-protector,fast-math")
//#pragma GCC target("sse,sse2,sse3,ssse3,sse4,popcnt,abm,mmx,tune=native")
//OPTIMIZATIONS
#include <bits/stdc++.h>
#include<combo.h>
typedef long long ll;
typedef unsigned long long uu;
typedef long long int lll;
typedef unsigned long long int uuu;
using namespace std;
#define watch(x) cerr << "\n" \
<< (#x) << " is " << (x) << endl
#define cel(x, y) 1 + ((x - 1) / y)
const double PI = 3.141592653589793238463;
const int MOD = 1000000007;
const int INF = 0x3f3f3f3f;
/*
$alil03
URL: url
Solution Begins here
*/
string guess_sequence(int n)
{
char first = 'A';
if(press("A") == 1)
{
first = 'A';
}
else if(press("B") == 1)
{
first = 'B';
}
else if(press("X") == 1)
{
first = 'X';
}
else if(press("Y") == 1)
{
first = 'Y';
}
int temp = n;
n--;
string s = "ABXY";
string ans = "";
ans += first;
while(n--)
{
for(int i = 0; i<4; i++)
{
if(s[i] == first)
{
continue;
}
if(press(ans + s[i]) == temp-n)
{
ans += s[i];
break;
}
}
}
return ans;
}
