0 used instead of "who" as the object of a verb or preposition:
1 used as the object of a verb or after a preposition when referring to a particular person or when adding information about a person just mentioned:
2 used esp. in questions as the object of a verb or after a preposition, when asking which person or people, or when asking what someone’s name is:
We can complete it step by step however long the road is and it can't be completed however short the road is if you don't even mark your footprint.