format sub categories

Hello,

I would like to do a import of products.

For the categories, the format is “cat name 1 > cat name 2 > cat name 3” for the level of categories.

But for the products which are in the level 1 and the level 3 but not in the level 2, what is the format please ?

I try this : “cat name 1 > > cat name 3” , but the product is unclassified.

Regards,