Unique Domain or Unique URL impacts PR?

Let's say my website is x and i have 2 backlinks from y, namely y1 and y2. Does the PR from each url (same domain) impact my site or does Google just count the PR from one of those urls? Google chooses the highest PR if both are indexed?

Any input? I would assume only unique domains count. So having 2 urls from the same domain would be worthless.