#include<bits/stdc++.h>
using namespace std;
#define mem(a,b) memset(a,b,sizeof(a))
typedef long long LL;
typedef pair<int,int> PII;
#define X first
#define Y second
inline int read()
{
	int x=0,f=1;char c=getchar();
	while(!isdigit(c)){if(c=='-')f=-1;c=getchar();}
	while(isdigit(c)){x=x*10+c-'0';c=getchar();}
	return x*f;
}
int T,a,b,c,d;
int main()
{
	T=read();
	while(T--)
	{
		a=read();b=read();c=read();d=read();
		if(a<c)
		{
			if(b>=d)
			{
				puts("AB//CD");
			}
			else if(c>d)
			{
				puts("AB//CD");
			}
			else
			{
				puts("AB//DC");
			}
		}
		else if(a>c)
		{
			if(b<=d)
			{
				puts("AB//DC");
			}
			else if(a>b)
			{
				puts("AB//DC");
			}
			else
			{
				puts("AB//CD");
			}
		}
		else
		{
			if(b>d)
			{
				puts("AB//CD");
			}
			else
			{
				puts("AB//DC");
			}
		}
	}
	return 0;
}
/*
 
*/