question: Were M3 and M4 executive produced by a Chinese star of M1 and M2
query: SELECT count(*) WHERE {
  ?x0 ns:film.actor.film/ns:film.performance.film M1 .
  ?x0 ns:film.actor.film/ns:film.performance.film M2 .
  ?x0 ns:people.person.nationality ns:m.0d05w3 .
  M3 ns:film.film.executive_produced_by ?x0 .
  M4 ns:film.film.executive_produced_by ?x0
  }