Consider relations R(A,B,C) and S(C,D,E). R has 20,000 tuples and S has 45,000 tuples. 25 tuples of R fit on one block, and 30 tuples of S fit on one block. Further, S.C is the primary key in relation S, and there is clustering B+tree index on S.C with height 4. How many block transfer would an index nested loop join incur?