I had a list of categories from Amazon which were stored in a csv like this (semicolon separated 25234 entries):
Main Category;Subcat 1;Subcat 2;Subcat 3;Subcat 4;Subcat 5;Subcat 6;Subcat 7;Subcat 8
Appliances
Appliances;Dishwashers
Appliances;Dishwashers;Built-In Dishwashers...