question: Was a film 's prequel directed and written by M0 , M1 , and M2
query: SELECT count(*) WHERE {
  ?x0 ns:film.film.directed_by M0 .
  ?x0 ns:film.film.directed_by M1 .
  ?x0 ns:film.film.directed_by M2 .
  ?x0 ns:film.film.sequel ?x1 .
  ?x0 ns:film.film.written_by M0 .
  ?x0 ns:film.film.written_by M1 .
  ?x0 ns:film.film.written_by M2 .
  ?x1 a ns:film.film
  }