question: Was M1 executive produced by M2 , executive produced by M3 , and written by a art director
query: SELECT count(*) WHERE {
  ?x0 a ns:film.film_art_director .
  M1 ns:film.film.executive_produced_by M2 .
  M1 ns:film.film.executive_produced_by M3 .
  M1 ns:film.film.written_by ?x0
  }