Can your marry the niece of the sister-in-law of your grandmother?

The niece could be the daughter of the sister-in-law's sibling and not related to you, so you could marry her. However, the niece could also be your mother or your aunt, in which case you could not marry her. Erm, but whover readwhat this guy just wrote, I expect you're wondering WHY WOULD YOU EVEN BOTHER? DON'T YOU HAVE ANYTHING BETTER TO DO??