Automatically reply to mail if subject doesn't match criteria

Question

People send a lot of mail to my gmail. I need a way to categorize my mail.

I thought of subject filters. whenever somebody send mail with "support" or "sales" as subject gmail would automatically label it and remove from inbox.

But the main problem is that people don't follow this rules. most of incoming mail has subject "help please, it's urgent!!!", "problem with payment" etc.

I want to know, is there a way I can automatically (without me even checking the mail) send reply to sender saying that subject is incorrect if subject is not exactly "sales" or "support" and send that kind of mail to trash?

P.S. many people would suggest to use different mail accounts, but that's not an option in this case.

Answer 1

Use a filter:

- excludes the following keyword.