import sys,random,bisect
from collections import deque,defaultdict
from heapq import heapify,heappop,heappush
from itertools import permutations
from math import log,gcd

input = lambda :sys.stdin.buffer.readline()
mi = lambda :map(int,input().split())
li = lambda :list(mi())

X,Y,K,P = mi()

A,B = (X+Y-K+1)//2,(X+Y-K)//2

if X <= A and pow(-1,Y) == P:
    exit(print("Alice"))
if Y <= A and P == 1:
    exit(print("Alice"))
if X <= B and pow(-1,Y) != P:
    exit(print("Bob"))
if Y <= B and P == -1:
    exit(print("Bob"))

if K&1:
    print("Alice")
else:
    print("Bob")