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())
    g = [0] * (n + 1)
    g[1] = 0
    for i in range(2, n + 1):
        s = set()
        if i % 2 == 0:
            s.add(0)
        else:
            s.add(g[i // 2] ^ g[i // 2 + 1])
        if i >= 3:
            if i % 3 == 0:
                s.add(g[i // 3])
            elif i % 3 == 1:
                s.add(g[i // 3 + 1])
            else:
                s.add(g[i // 3])
        for x in count(0):
            if x not in s:
                g[i] = x
                break

    return 'A' if g[n] else 'B'


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()