X, Y, K, P = map(int, input().split())
AB = ["Bob", "Alice"]
A = "Alice"
B = "Bob"
T = X + Y
U = T - K
if U & 1:
    last = A
else:
    last = B
if P == 1 and Y <= -(-U // 2):
    ans = A
elif P == -1 and Y <= U // 2:
    ans = B
elif P == 1 and K & 1 == 0 and X <= -(-U // 2):
    ans = A
elif P == -1 and K & 1 == 1 and X <= -(-U // 2):
    ans = A
elif P == 1 and K & 1 == 1 and X <= U // 2:
    ans = B
elif P == -1 and K & 1 == 0 and X <= U // 2:
    ans = B
else:
    ans = last
print(ans)