Contact - How do contacts work?

Hello

I would like to start off by saying that we’re a job platform that offers different kinds of jobs on Instagram, and we ask our users to comment “Yes”, post which we DM them the job link that they’re looking for. 

We post everyday on Instagram and each job is different which means that each link is different too. 

My question is - 

Let’s say person ‘X’ comments on our video/reel, and Manychat sends them a DM, X is now a contact established with Manychat. Say the same X person comments on another video for another job link, and Manychat sends them a DM, will that be counted as 2 contacts, or just 1? 

Is there a limit to how many times can one person comment on different videos and get DMs? 

Also, I wanted to know if we automate for comments as well, if X comments, when they get a response via comments and DM, will it be considered as 1 contact or 2 contacts?

There is no clarification for this. 

Would appreciate if I could get some form of help!

Thanks.