N = int(input())

grundy = [0] * (101)
grundy[2] = 1

for i in range(3, N+1):
    tmp = set()
    if i & 1:
        tmp.add(grundy[i//2] ^ grundy[i//2 + 1])
    else:
        tmp.add(0)
    
    if i % 3 == 0:
        tmp.add(grundy[i//3])
    elif i % 3 == 1:
        tmp.add(grundy[i//3 + 1])
    else:
        tmp.add(grundy[i//3] ^ grundy[i//3 + 1] ^ grundy[i//3 + 2])
    
    g = 0
    while g in tmp:
        g += 1
    grundy[i] = g


if grundy[N] == 0:
    print('B')
else:
    print('A')