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