S1: Paragraphs are the building blocks of any write-up. P: A paragraph need not be pages together in length. Q: But actually a paragraph is a group of at least five sentences on the lower limit. R: In reality, unity and coherence, not length, constitute a real good paragraph. S: Many people define paragraphs in terms of their length. S6: Understanding of these makes one a good writer of paragraphs. Find the correct sequence of P, Q, R and S.