How many people have been the first one to scale a peak in the Yosemite Park?
SELECT DISTINCT COUNT(?uri) WHERE { ?x <http://dbpedia.org/ontology/locatedInArea> <http://dbpedia.org/resource/Yosemite_National_Park> . ?x <http://dbpedia.org/ontology/firstAscentPerson> ?uri  . ?uri <http://www.w3.org/1999/02/22-rdf-syntax-ns#type> <http://dbpedia.org/ontology/Person>}
Yosemite_National_Park