using System;
using System.IO;
using System.Linq;
using System.Text;
using System.Diagnostics;
using System.Collections.Generic;
using System.Text.RegularExpressions;
using Enu = System.Linq.Enumerable;

class Program
{
    int?[] memo = new int?[101];

    void Solve()
    {
        int N = reader.Int();
        Console.WriteLine(Grundy(N) != 0 ? "A" : "B");
    }

    int Grundy(int N)
    {
        if (N < 2) return 0;
        if (memo[N].HasValue) return memo[N].Value;
        
        var set = new HashSet<int>();
        set.Add(Grundy(N / 2) ^ Grundy(N - N / 2));
        if (N >= 3)
        {
            int[] next = new int[] { N / 3, N / 3, N / 3 };
            for (int i = 0; i < N % 3; i++) next[2 - i]++;
            set.Add(Grundy(next[0]) ^ Grundy(next[1]) ^ Grundy(next[2]));
        }
        int g = 0;
        while (set.Contains(g)) g++;
        memo[N] = g;
        return g;
    }



    Reader reader = new Reader(Console.In);
    static void Main() { new Program().Solve(); }
}

class Reader
{
    private readonly TextReader reader;
    private readonly char[] separator = { ' ' };
    private readonly StringSplitOptions removeOp = StringSplitOptions.RemoveEmptyEntries;
    private string[] A = new string[0];
    private int i;

    public Reader(TextReader r) { reader = r; }
    public bool HasNext() { return Enqueue(); }
    public string String() { return Dequeue(); }
    public int Int() { return int.Parse(Dequeue()); }
    public long Long() { return long.Parse(Dequeue()); }
    public double Double() { return double.Parse(Dequeue()); }
    public int[] IntLine() { var s = Line(); return s == "" ? new int[0] : Array.ConvertAll(Split(s), int.Parse); }
    public int[] IntArray(int N) { return Enu.Range(0, N).Select(i => Int()).ToArray(); }
    public int[][] IntGrid(int H) { return Enu.Range(0, H).Select(i => IntLine()).ToArray(); }
    public string[] StringArray(int N) { return Enu.Range(0, N).Select(i => Line()).ToArray(); }
    public string Line() { return reader.ReadLine().Trim(); }
    private string[] Split(string s) { return s.Split(separator, removeOp); }
    private bool Enqueue()
    {
        if (i < A.Length) return true;
        string line = reader.ReadLine();
        if (line == null) return false;
        if (line == "") return Enqueue();
        A = Split(line);
        i = 0;
        return true;
    }
    private string Dequeue() { Enqueue(); return A[i++]; }
}