Bob is red. Dave is smart. Erin is green. Gary is green. If Erin is smart then Erin is young. If something is big and young then it is red. All quiet things are big. If something is blue and quiet then it is green. If something is big and smart then it is young. Young, smart things are blue. If Erin is green and Erin is big then Erin is smart. All young, green things are quiet.
Erin is not green.