There are eight students in a graduate computer science class. Each student has a web page and each web page has a link to exactly two web pages of other students in the class. Show that for each student s, there exists a student s such that (1) there is no link from the web page of s to the web page of s and (2) for each student s for whom there is a link from the web page of s to the web page of s, there is no link from the web page of s to the web page of s.