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

# Calculate the required parity R
R = (Y % 2) ^ (1 if P == -1 else 0)

t_min = max(0, T - X)
t_max = min(Y, T)

# Check if there's any t in [t_min, t_max] with t % 2 == R
has_solution = False
if t_max >= t_min:
    first_t = t_min if t_min % 2 == R else t_min + 1
    if first_t <= t_max:
        has_solution = True

if not has_solution:
    print("Bob")
else:
    C = min(T, min(X, Y))
    if X <= Y:
        forced_flips = max(0, T - C)
    else:
        forced_flips = 0

    # Determine if during C moves, all -1s or all +1s are taken
    if C == Y:
        flips_during_parity = Y % 2
    elif C == X:
        flips_during_parity = 0
    else:
        desired_parity = (R - forced_flips) % 2
        if C % 2 == 0:
            flips_during_parity = (1 - desired_parity) % 2
        else:
            flips_during_parity = desired_parity

    total_parity = (forced_flips + flips_during_parity) % 2
    if total_parity == R:
        print("Alice")
    else:
        print("Bob")