From how many countries did the aeroplanes designed by Alexander Lippisch originate?
SELECT DISTINCT COUNT(?uri) WHERE { ?x <http://dbpedia.org/property/designer> <http://dbpedia.org/resource/Alexander_Lippisch> . ?x <http://dbpedia.org/property/nationalOrigin> ?uri  . ?uri <http://www.w3.org/1999/02/22-rdf-syntax-ns#type> <http://dbpedia.org/ontology/Country>}
Alexander_Lippisch