I work in Spain, we don't have sick days. If the doctor says we are not apt to work, we take a leave intil the doctor says so. Indefinitely. No maximum. As long as the doctor says.
This limit thing is so weird. Yeah, you can use them as vacation of you are healthy but that's an abuse and then when you need them you will be vulnerable without days. It's better to have infinite days, to be used only when you are actually sick, as stated by your doctor.