White pigmented shellac to cover the water stain and to prevent the stain from bleeding thru paint. Then whatever ceiling paint. Brand doesn't much matter, IMO. Or paint it with the white wall paint that you already have.

White shellac, and then primer is what I use, and hopefully still have paint used for that ceiling, so can touch it up, otherwise, you will be painting the entire ceiling. There are too many shades of white.

Benjamin Moore 508 dead flat ceiling paint.

It covers extremely well in one coat over most aged whites. Application is foolproof and will not leave lap lines when rolling. It also touches up well just in case the water spots return. You won't have to roll the whole ceiling again. It's the best ceiling paint on the market. Seal the stain first with with a spray can of Kilz or BIN. If you are in a hurry use BIN shellac primer because It'll dry in 10 minutes.

Thanks, guys.

Eco Star Painting, first of all, thanks for great reply, appreciated. Аfter your reply I read some articles, and indeed Benjamin Moore seems to be a great ceiling paints brand. I think I will buy 508. But there is only one moment left. There is also Benjamin Moore Muresco which is also a good choice from what I can gather. Could you please tell me something about Muresco and why 508 is better? Thanks!

The 508 is an ultra flat or "dead flat" that will minimize imperfections and you won't see roller lines or marks. It hides extremely well--better than any ceiling paint I've ever used---- and is 100% acrylic. The Muresco is a vinyl-acrylic which is made with less quality ingredients.