Were M3 and M4 influenced by a film producer and influenced by a Mexican person
SELECT count(*) WHERE {
?x0 a ns:film.producer .
?x1 a ns:people.person .
?x1 ns:people.person.nationality ns:m.0b90_r .
M3 ns:influence.influence_node.influenced_by ?x0 .
M3 ns:influence.influence_node.influenced_by ?x1 .
M4 ns:influence.influence_node.influenced_by ?x0 .
M4 ns:influence.influence_node.influenced_by ?x1
}