import java.math.BigInteger;
import java.util.*;
public class Main {
	static int rec(int x){
		if(grandy[x]!=-1) return grandy[x];
		
		Set<Integer> set = new HashSet<>();
		set.add(rec(x/2)^rec((x+1)/2));
		if(x>=3){
			set.add(rec(x/3)^rec((x+1)/3)^rec((x+2)/3));
		}
		int res=0;
		while(set.contains(res)) res++;
		return grandy[x]=res;
		}
	static int[] grandy;
	public static void main(String[] args) {
		Scanner sc=new Scanner(System.in);
		grandy = new int[101];
		Arrays.fill(grandy, -1);
		grandy[1]=0;
		for(int i=1;i<101;i++) grandy[i]=rec(i);
		if(grandy[sc.nextInt()]==0){
			System.out.println("B");
		}else{
			System.out.println("A");
		}
	}
}