google chrome – Search for old emails that are NOT starred (Gmail)

Gmail has a search bar where you can filter emails. For example, to see emails from December 2019:

before:2020/01/01 after:2019/11/30 

Or to see emails before the start of 2020 which are starred:

before:2020/01/01 is:starred

But how do you ask for “Emails before the start of 2020 and which are NOT starred? I’ve tried combinations like before:2020/01/01 NOT is:starred or {before:2020/01/01} - {before:2020/01/01 is:starred} but nothing works.

This Google help article covers more options, but I wasn’t able to work out a way to select a negation (like the C/C++ ! operator).