What's the idiom that two non's add up to three non's and two non's add up to one yes?

What's the idiom that two non's add up to three non's and two non's add up to one yes?

have a maggot in one's head
Feifei: originally a Buddhist language, it means the realm of illusion. I want to go to a very mysterious and illusory place. It describes a completely unrealistic fantasy
I don't quite understand what the landlord means
I hope it will help you