Do you know WHO I am?

　　"No, as a matter of fact I don't," replied the professor with an air of sarcasm in his voice.

　　"Are You sure that you don't know WHO I am?!" the student asked again.

　　"No, and I don't care." replied the professor with an air of superiority. "Good," replied the student, who quickly lifted the stack of completed exams, stuffed his in the middle, and walked out of the room.