Question: How many countries surround the sea into which the Upper Neratva flow?
SPARQL query:
PREFIX rdf: <http://www.w3.org/1999/02/22-rdf-syntax-ns#>
PREFIX onto: <http://dbpedia.org/ontology/>
SELECT DISTINCT COUNT(?uri) WHERE { <http://dbpedia.org/resource/Upper_Neretva> onto:riverMouth ?x . ?x onto:country ?uri  . ?x rdf:type onto:Sea}