Charlie is blue. Charlie is red. Charlie is rough. Dave is blue. Dave is furry. Dave is nice. Dave is quiet. Dave is red. Dave is rough. Dave is smart. Erin is not blue. Erin is not furry. If Dave is nice and Dave is smart then Dave is rough. All smart things are quiet. If Erin is nice and Erin is not blue then Erin is quiet.
Dave is smart.