question: Did M1 and M3 star M2 and star a screenwriter 's actor
query: SELECT count(*) WHERE {
  ?x0 ns:film.actor.film/ns:film.performance.character ?x1 .
  ?x1 a ns:film.writer .
  M1 ns:film.film.starring/ns:film.performance.actor ?x0 .
  M1 ns:film.film.starring/ns:film.performance.actor M2 .
  M3 ns:film.film.starring/ns:film.performance.actor ?x0 .
  M3 ns:film.film.starring/ns:film.performance.actor M2
  }