def F(P, X, Y, K):
    if P == 1 and X % 2 == 0 and X < Y:
        if K <= Y - X:
            return (Y + K + 1) % 2
        return (Y + K) % 2
    if P == 1 and X % 2 == 0 and X >= Y:
        if K <= X - Y:
            return (Y + 1) % 2
        return (Y + K) % 2
    if P == 1 and X % 2 == 1 and X <= Y:
        return (K + Y + 1) % 2
    if P == 1 and X % 2 == 1 and X > Y:
        if K <= X - Y:
            return (Y + 1) % 2
        return (K + Y + 1) % 2
    assert P == -1
    if X % 2 == 0 and X <= Y:
        return (Y + K) % 2
    if X % 2 == 0 and X > Y:
        if K <= X - Y:
            return Y % 2
        return (Y + K) % 2
    if X % 2 == 1 and X < Y:
        if K <= Y - X:
            return (Y + K) % 2
        return (Y + K + 1) % 2
    if X % 2 == 1 and X >= Y:
        if K <= X - Y:
            return Y % 2
        return (Y + K + 1) % 2
    return -1


X, Y, K, P = map(int, input().split())
print("Alice" if F(P, X, Y, K) else "Bob")