You could make 23 of the groups have 2 people pass through, and 2 of the groups only have 1 person pass through, leading to 48, 6 groups of 8, then top 3 of those, 3 groups of 18, then 2 groups where top 3 goes to finals and 1 group where top 2 goes to finals, for the last top 8. That would make...