Excel text removal for non static strings

Hi,
I have a couple issues that Im in need of help with. The first is removing text from each cell in a column when it is delimited by '-'

I want to remove everything after the last '-'

Something like this:

thing1-thing1a-sometext
thing1-thing1bbb-sometext
thing2-thing2aajah-sometext

So, in this example, how would I remove 'sometext' from each of the above cells?

Thank you!