Absent minded professor?

this is a funny story I remember from when I was a kid:

There is an absent minded professor sitting on a train..he couldn't remember anything..so whatever events took place he wrote it down in a little black book. So while sitting there..a man walks up to him sits down and says:hey professor..have you ever been to Pittsburgh? So of course he takes out the little black book saying Pittsburgh over and over and finally he says..YES I've been to Pittsb urgh. The other man further inquires if he ever met a woman who's name was lana smith..so the professor looks up the name..yes..i met a woman named lana smith in pittsburgh..then the other man asks.did you have an affair with a woman by that name.the professor looks it up under affairs..YES i had an affair with a woman by the name of lana smith.."well.the other man says out loud..I happen to be mr smith and I don't like it"..so the professor looks it up under opinions..then he replies..no i didn't either