I can't be certain how many degrees separated the two are, but I have established a lower bound on the answer
Let d:(x,y)->n be the degrees of separation between x and y. Since d(x,y)=0 implies x=y, and we know that FB and HN are not identical, we have d(FB,HN)>0.
Then, since d takes integral values we know that d(FB,HN)>=1 in any case.