Difficult because they are actually very strong at that age but when my daughter is in a foul mood and lashing out at me I'm just trying to avoid punches and stop me or her coming to harm without trying to harm her.
But I would guess it would be more likely I would get tired out holding them off and therefore too weak to defend myself at some point.
Also if it is one kid at a time it would be easier than 100 all after you at once.
So I'd say
one on one: 40
Multiple kids at once: 20