And then there's the Company, which is five Groups plus or minus five Sections of Heavy Weapons. Don't get confused though, because a Section of Heavy Weapons isn't six men, like an Infantry Section, it's seven. That's because they have an ammo bearer, which is traditional.
So a Company is 359. The nine extra guys are message runners.
But the main organizational unit, at least as far as infantry is concerned, is a Group.
A Group is three Squads, a Command Squad, and four Sections. That's 63 personnel. You can also call it an Ag, which is short for Aggregation, but nobody ever says the whole word.