question: Did M2 edit a film 's sequel and prequel and edit a prequel of M0
query: SELECT count(*) WHERE {
  ?x0 ns:film.film.sequel M0 .
  ?x1 ns:film.film.prequel ?x2 .
  ?x1 ns:film.film.sequel ?x2 .
  ?x2 a ns:film.film .
  M2 ns:film.editor.film ?x0 .
  M2 ns:film.editor.film ?x1
  }