Bob is blue. Bob is not green. Bob is round. Bob is white. Bob is young. Dave is blue. Dave is green. Dave is round. Dave is young. Erin is red. Erin is white. Erin is not young. If Dave is not young then Dave is not blue. If Bob is blue and Bob is round then Bob is not quiet. If something is green and not round then it is not young.
Bob is not green.