Hello [name]! Thanks for joining the GMC. Before making any posts in the Tech Support forum, can we suggest you read the forum rules? These are simple guidelines that we ask you to follow so that you can get the best help possible for your issue.
I bought license from steam. And there writes that you have 3 install rights. My question is, if I make clean installation to my pc, format everything and reinstall again. Will my 3 rights be 2?
I'm pretty sure the answer here is no... the YoYo Account page is what controls this and not Steam, and it also shows the installs you have currently activated. Basically, you can have GMS installed on up to three machines, but if you want to install it on a fourth machine, then you need to de-authorise one from your YoYo Account.