#!/usr/bin/env python3
# -*- coding: utf-8 -*-

memo = [-1] * 101
memo[1] = 0
memo[2] = 1

def gr(n):
    global memo
    if memo[n] != -1:
        return memo[n]

    #1つの山を2つに分ける
    n1 = n // 2
    n2 = n - n1
    gr2 = gr(n1) ^ gr(n2)

    #1つの山を3つに分ける
    n3 = n // 3
    n4 = (n - n3) // 2
    n5 = n - n3 - n4
    gr3 = gr(n3) ^ gr(n4) ^ gr(n5)

    res = 0
    while gr2 == res or gr3 == res:
        res += 1
    memo[n] = res

    return memo[n]

n = int(input())

if gr(n):
    print("A")
else:
    print("B")