Best way to code this information - list

I’m wondering what would the best to way represent this data in AS.

Topic
— Point
------ Detail
------ Detail
----------Sub Detail
---- Point
------ Detail
------ Detail

So, my information will be presented in 4 levels: Topic -> Point -> Detail -> Sub Detail. Each level of these will be dynamic, I could have 0 or 1k. There is the hierarchy required, so they can’t enter a detail, without having a point and topic to place it in. But the addition/subtraction of sub items will not come in any required order.

I don’t know if I should use an Array, an object, a dictionary object, an array of objects. I really just need some guidance here. thanks.