How many software run on operating system Microsoft Windows?
SELECT DISTINCT COUNT(?uri) WHERE {?uri <http://dbpedia.org/ontology/operatingSystem> <http://dbpedia.org/resource/Microsoft_Windows>  . ?uri <http://www.w3.org/1999/02/22-rdf-syntax-ns#type> <http://dbpedia.org/ontology/Software>}
Microsoft_Windows