X, Y, K, P = map(int, input().split())

T = X + Y - K
desired_parity = 1 if P == -1 else 0
T_parity = (Y % 2) ^ desired_parity

min_remove = max(0, T - X)
max_remove = min(T, Y)

if min_remove > max_remove:
    print("Bob")
else:
    if (min_remove % 2) == (max_remove % 2):
        if (min_remove % 2) == T_parity:
            print("Alice")
        else:
            print("Bob")
    else:
        if T % 2 == 1:
            print("Alice")
        else:
            print("Bob")