For how many movies have the music composer composed music, who have collaborated with Yes?
SELECT DISTINCT COUNT(?uri) WHERE { ?x <http://dbpedia.org/ontology/associatedMusicalArtist> <http://dbpedia.org/resource/Yes_(band)> . ?uri <http://dbpedia.org/ontology/musicComposer> ?x  . ?uri <http://www.w3.org/1999/02/22-rdf-syntax-ns#type> <http://dbpedia.org/ontology/Film>}
Yes_(band)