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

T = X + Y - K
target_parity = Y % 2 if P == 1 else (Y - 1) % 2

if T <= Y:
    if T % 2 == 1:
        print("Alice")
    else:
        print("Bob")
else:
    if (Y % 2) == target_parity:
        print("Alice")
    else:
        print("Bob")