Setting up a VPS

Hello everyone, I would have searched through the threads better, but with the search being broken currently, I'll simply make a thread.

I'm about to buy a VPS, and they're asking for a NS1 and NS2 Prefix, which I have only a limited understanding of what that is, or what I should put. I believe it has something to do with my IP address(es) so if someone could help me figure it out that'd be great.

I'll be using virpus.com, if that helps any. I understand that this is probably a very poor question for someone who wants to use a VPS, but it's to only run one bot and the 24/7 use of my PC is out of the question.

Thanks in advance,
Mike