import sys
from itertools import count
from math import gcd

from typing import List, Tuple


def int1(x: str, /): return int(x) - 1


def input(): return sys.stdin.readline().rstrip('\n')


def dbg(*args, **kwargs):
    print(*(repr(arg) for arg in args), *(f'{k}: {repr(v)}' for k, v in kwargs.items()), sep='; ', file=sys.stderr)


def main():
    n = int(input())
    ret = True
    while True:
        if n == 1:
            break
        if n % 2 == 0:
            ret = not ret
            break  # Win
        elif n % 3 == 0 or n % 3 == 2:
            n //= 3
            ret = not ret
        else:
            n = (n + 2) // 3
            ret = not ret

    return 'B' if ret else 'A'


def _start():
    ret = main()

    if ret is not None:
        if isinstance(ret, List) or isinstance(ret, Tuple):
            print(*ret)
        else:
            print(ret)


if __name__ == '__main__':
    _start()