question: Did M3 and M4 marry a art director that M1 and M2 starred
query: SELECT count(*) WHERE {
  ?x0 a ns:film.film_art_director .
  ?x0 ns:film.actor.film/ns:film.performance.film M1 .
  ?x0 ns:film.actor.film/ns:film.performance.film M2 .
  FILTER ( M3 != ?x0 ) .
  FILTER ( M4 != ?x0 ) .
  M3 ns:people.person.spouse_s/ns:people.marriage.spouse|ns:fictional_universe.fictional_character.married_to/ns:fictional_universe.marriage_of_fictional_characters.spouses ?x0 .
  M4 ns:people.person.spouse_s/ns:people.marriage.spouse|ns:fictional_universe.fictional_character.married_to/ns:fictional_universe.marriage_of_fictional_characters.spouses ?x0
  }