question: Did a Mexican writer of M0 influence M1 and influence M2
query: SELECT count(*) WHERE {
  ?x0 ns:film.writer.film M0 .
  ?x0 ns:influence.influence_node.influenced M1 .
  ?x0 ns:influence.influence_node.influenced M2 .
  ?x0 ns:people.person.nationality ns:m.0b90_r
  }