In countries that do not exploit workers, if the doctor writes you a sick leave, you are at sick leave for that time. If doctor writes you 6 months, you can be away 6 months with full pay. In general company pays some initial weeks, and the system pays the rest.

So there is no max or min.

Also in many countries if you are in your paid vacation, and you get sick, you move for sick leave, and those days do not count as used vacation.

Here specifically it's three days off (each time, not total) and then you need to get an official doctor declaration to stay home longer (which makes sense, if you've been sick for several days you should see a doctor anyway, and it's free, so why not).

And if the doctor says you're too sick to work, even if it's due to your mental health then you're off for as long as they say, with a compensation scheme that involves both your company and the government dealing with the cost for certain periods and so on.