question: Were M3 and M4 edited by a American writer of M0 and M1
query: SELECT count(*) WHERE {
  ?x0 ns:film.writer.film M0 .
  ?x0 ns:film.writer.film M1 .
  ?x0 ns:people.person.nationality ns:m.09c7w0 .
  M3 ns:film.film.edited_by ?x0 .
  M4 ns:film.film.edited_by ?x0
  }