I'm nearly positive it's 2.Wippit Guud said:And we're sure it's 1 level and not 2?
IIRC one example in the book refers to a character with a level split of 9/3, picking up a new class to become 9/3/1. If the 9th-level class is favored, the character suffers no penalty. It's possible that I'm wrong here, but I really don't think so.
(Unfortunately, since this isn't in the SRD, I can't post the exact quote right at the moment... I'll do so when I get home unless someone beats me to it.)