using System;
using System.Collections.Generic;
using System.Linq;

public class Program
{
    static int[] memo = { };

    static int GetGrundy(int count)
    { 
        if(memo[count] != -1)
            return memo[count];

        Dictionary<int, int> dic = new Dictionary<int, int>();
        if (count >= 2 && count % 2 == 0)
        {
            int grundy = GetGrundy(count / 2) ^ GetGrundy(count / 2);
            if(!dic.ContainsKey(grundy))
                dic.Add(grundy, 1);
        }
        if (count >= 2 && count % 2 == 1)
        {
            int grundy = GetGrundy(count / 2) ^ GetGrundy(count / 2 + 1);
            if (!dic.ContainsKey(grundy))
                dic.Add(grundy, 1);
        }
        if (count >= 3 && count % 3 == 0)
        {
            int grundy = GetGrundy(count / 3) ^ GetGrundy(count / 3) ^ GetGrundy(count / 3);
            if (!dic.ContainsKey(grundy))
                dic.Add(grundy, 1);
        }
        if (count >= 3 && count % 3 == 1)
        {
            int grundy = GetGrundy(count / 3) ^ GetGrundy(count / 3) ^ GetGrundy(count / 3 + 1);
            if (!dic.ContainsKey(grundy))
                dic.Add(grundy, 1);
        }
        if (count >= 3 && count % 3 == 2)
        {
            int grundy = GetGrundy(count / 3) ^ GetGrundy(count / 3 + 1) ^ GetGrundy(count / 3 + 1);
            if (!dic.ContainsKey(grundy))
                dic.Add(grundy, 1);
        }

        int ret = 0;
        while (true)
        {
            if(!dic.ContainsKey(ret))
                break;
            ret++;
        }
        memo[count] = ret;
        return ret;
    }

    static void Main()
    {
        int N = int.Parse(Console.ReadLine());
        memo = new int[N + 1];
        for (int i = 0; i <= N; i++)
            memo[i] = -1;

        if (GetGrundy(N) != 0)
            Console.WriteLine("A");
        else
            Console.WriteLine("B");
    }
}