Was M1 a screenwriter that M3 was influenced by , a person was influenced by , and M4 was influenced by
SELECT count(*) WHERE {
?x0 a ns:people.person .
M1 a ns:film.writer .
M1 ns:influence.influence_node.influenced ?x0 .
M1 ns:influence.influence_node.influenced M3 .
M1 ns:influence.influence_node.influenced M4
}