question: Did M5 and M6 executive produce a film that was executive produced by M3 and M4 and starred M1 and M2
query: SELECT count(*) WHERE {
  ?x0 a ns:film.film .
  ?x0 ns:film.film.executive_produced_by M3 .
  ?x0 ns:film.film.executive_produced_by M4 .
  ?x0 ns:film.film.starring/ns:film.performance.actor M1 .
  ?x0 ns:film.film.starring/ns:film.performance.actor M2 .
  M5 ns:film.producer.films_executive_produced ?x0 .
  M6 ns:film.producer.films_executive_produced ?x0
  }