Each of P, Q, R, S, T, U and V, has an exam on a different day of a week starting from Monday and ending on Sunday of the same week. R has an exam on Thursday. Exactly 4 people have their exam between U and Q, neither of whom has an exam on Sunday. P has an exam immediately before S. V does not have an exam on Friday. U does not have an exam after S. How many people have an exam after Q?