question: Was M2 's sequel executive produced by M0 , executive produced by M1 , and executive produced by a person
query: SELECT count(*) WHERE {
  ?x0 ns:film.film.executive_produced_by ?x1 .
  ?x0 ns:film.film.executive_produced_by M0 .
  ?x0 ns:film.film.executive_produced_by M1 .
  ?x0 ns:film.film.prequel M2 .
  ?x1 a ns:people.person
  }