#include <iostream>
#include <vector>
#include <cstdio>
#include <sstream>
#include <map>
#include <string>
#include <algorithm>
#include <queue>
#include <cmath>
#include <set>
using namespace std;

int grundy(int x){
	if(x==0) return 0;

	set<int> s;

	if(x/3>0){
		int a = x/3;
		int b = (x-a)/2;
		int c = x-a-b;

		s.insert( grundy(a) ^ grundy(b) ^ grundy(c) );
	}

	if(x/2 > 0){
		int a = x/2;
		int b = x-a;

		s.insert( grundy(a) ^ grundy(b) );
	}

	int g = 0;
	while(s.count(g) != 0) g++;
	return g;
}

int main(){
	int N;
	cin >> N;
	
	int ans = grundy(N);

	cout << (ans==0?"B":"A") << endl;

	return 0;
}