gn = [-1] * 101
gn[1] = 0


def grundy_number(n):
    if gn[n] != -1:
        return gn[n]

    s = set()
    a = n // 2
    b = n - a
    s.add(grundy_number(a) ^ grundy_number(b))
    if n >= 3:
        a = n // 3
        b = n - a
        c = b // 2
        b -= c
        s.add(grundy_number(a) ^ grundy_number(b) ^ grundy_number(c))

    res = 0
    while res in s:
        res += 1
    gn[n] = res
    return res


def main():
    N = int(input())
    print('A' if grundy_number(N) else 'B')


if __name__ == '__main__':
    main()