#include <bits/stdc++.h>

using namespace std;

void validate(string s)
{
	int n = (int)s.size();
	assert(n >= 1 && n <= 500);
	for ( int i = 0; i < n; i++ ) {
		assert(s[i] >= 'a' && s[i] <= 'z');
	}
}

int cnt_s[26];
int cnt_t[26];

int main()
{
	int tc, n;
	string s, t;
	bool flag;
	
	cin >> tc;
	assert(tc >= 1 && tc <= 500);
	
	while ( tc-- ) {
		cin >> s >> t;
		
		validate(s);
		validate(t);
		assert(s.size() == t.size());
		
		memset(cnt_s, 0, sizeof(cnt_s));
		memset(cnt_t, 0, sizeof(cnt_t));
		
		n = (int)s.size();
		
		for ( int i = 0; i < s.size(); i++ ) {
			cnt_s[s[i] - 'a']++;
			cnt_t[t[i] - 'a']++;
		}
		
		flag = false;
		
		for ( int i = 0; i < 26; i++ ) {
			if ( cnt_s[i] > 1 && cnt_t[i] == 0 ) {
				flag = true;
				break;
			}
		}
		
		if ( flag ) {
			puts("A");
			continue;
		}
		
		bool f1 = false, f2 = false;
		
		for ( int i = 0; i < 26; i++ ) {
			if ( cnt_s[i] > 0 && cnt_t[i] == 0 ) f1 = true;
			if ( cnt_t[i] > 0 && cnt_s[i] == 0 ) f2 = true;
		}
		
		if ( !f2 && f1 ) {
			puts("A");
			continue;
		}
		
		puts("B");
			
	}
	
	return 0;
}