x,y,k,p=list(map(int,input().split()))
if (x+y-k)%2==0:
    if y<=x-k and p==1:
        print("Alice")
    elif x<y-k and  pow(-1,y-k)==p:
        print("Alice")
    else:
        print("Bob")
elif y<=x-k-1 and p==-1:
    print("Bob")
elif x<=y-k-1 and pow(-1,y-k)==p:
    print("Bob")
else:
    print("Alice")