memo = [-1] * 101
memo[1] = 0
memo[2] = 1
def grundy(n):
    global memo
    if memo[n] != -1:
        return memo[n]

    # 2 で割る
    n1 = n // 2
    n2 = n - n1
    grundy2 = grundy(n1) ^ grundy(n2)

    # 3 で割る
    n1 = n // 3
    n2 = (n - n1) // 2
    n3 = n - n1 - n2
    grundy3 = grundy(n1) ^ grundy(n2) ^ grundy(n3)

    for k in range(3):
        if k != grundy2 and k != grundy3:
            memo[n] = k
            return k

if __name__ == '__main__':
    N = int(input())
    if grundy(N):
        print('A')
    else:
        print('B')