using System;
using System.Collections;
using System.Collections.Generic;
 
class TEST{
	static void Main(){
		Sol mySol =new Sol();
		mySol.Solve();
	}
}

class Sol{
	public void Solve(){
		//N<=1e18でもいけます
		gr=new Dictionary<long,int>();
		gr[1]=0;
		int ret=dfs(N);
		Console.WriteLine(ret==0?"B":"A");
		
	}
	
	Dictionary<long,int> gr;
	
	int dfs(long x){
		if(gr.ContainsKey(x))return gr[x];
		HashSet<int> H=new HashSet<int>();
		if(x>1)H.Add( dfs(x/2)^dfs( (x+1)/2 ));
		if(x>2)H.Add( dfs(x/3)^dfs( (x+1)/3 )^dfs( (x+2)/3 ));
		int ret=0;
		while(H.Contains(ret))ret++;
		return gr[x]=ret;
	}
	
	long N;
	public Sol(){
		N=rl();
	}

	static String rs(){return Console.ReadLine();}
	static int ri(){return int.Parse(Console.ReadLine());}
	static long rl(){return long.Parse(Console.ReadLine());}
	static double rd(){return double.Parse(Console.ReadLine());}
	static String[] rsa(){return Console.ReadLine().Split(' ');}
	static int[] ria(){return Array.ConvertAll(Console.ReadLine().Split(' '),e=>int.Parse(e));}
	static long[] rla(){return Array.ConvertAll(Console.ReadLine().Split(' '),e=>long.Parse(e));}
	static double[] rda(){return Array.ConvertAll(Console.ReadLine().Split(' '),e=>double.Parse(e));}
}