Import menu tree to custom menu from csv or xml, many nested menu points

what would you recommend to import about 6000 menu items (yes it is ab big catalog with many nested categroies, depth about 6) to a custom menu in WordPress.
I have a text file with the following structure with about 6000 rows.

Car {link}
-Parts {link}
--Mirrors {link}
--Wheelspinners {link}
House {link}
-Kitchen {link}
--Cutlery {link}
---Forks {link}
---Knifes {link}
--Dishes {link}
-Bedroom {link}
...

Some categories can exist more than one time (e.g. Knifes could be also find under the “Hunting” category. The link in the brakets is unique and shuold be the link target of the menu point.

Thanks in advance for your recommendations and help.