question: Was M3 written by M4 , written by M0 's director , and written by a editor of M1 and M2
query: SELECT count(*) WHERE {
  ?x0 ns:film.director.film M0 .
  ?x1 ns:film.editor.film M1 .
  ?x1 ns:film.editor.film M2 .
  M3 ns:film.film.written_by ?x0 .
  M3 ns:film.film.written_by ?x1 .
  M3 ns:film.film.written_by M4
  }