question: Was M1 executive produced by M2 and M3 , executive produced by M4 , and directed by a person
query: SELECT count(*) WHERE {
  ?x0 a ns:people.person .
  M1 ns:film.film.directed_by ?x0 .
  M1 ns:film.film.executive_produced_by M2 .
  M1 ns:film.film.executive_produced_by M3 .
  M1 ns:film.film.executive_produced_by M4
  }