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

toru=X+Y-K

if toru%2==0:
    if X<=toru//2:
        if K%2==0 and P==1:
            print("Alice")
            exit()
        if K%2==1 and P==-1:
            print("Alice")
            exit()

    if Y<=toru//2:
        if P==1:
            print("Alice")
            exit()
    print("Bob")

else:
    if X<=(toru-1)//2:
        if K%2==0 and P==-1:
            print("Bob")
            exit()
        if K%2==1 and P==1:
            print("Bob")
            exit()

    if Y<=(toru-1)//2:
        if P==-1:
            print("Bob")
            exit()
    print("Alice")