N = int(input())
grundy = [-1, 0, 1]
for i in range(101):
    if i == 0 or i == 1 or i == 2:
        continue;
    if i % 2 == 0:
        a = 0
    else:
        a = grundy[i // 2] ^ grundy[i // 2 + 1]
    if i % 3 == 1:
        b = grundy[i // 3 + 1]
    else:
        b = grundy[i // 3]
    g = 0
    while g == a or g == b:
        g+=1
    grundy.append(g)
print("B" if grundy[N]==0 else "A")