Question: Give me the number of home stadiums of teams managed by John Spencer.
SPARQL query:
PREFIX prop: <http://dbpedia.org/property/>
PREFIX onto: <http://dbpedia.org/ontology/>
SELECT DISTINCT COUNT(?uri) WHERE { ?x prop:manager <http://dbpedia.org/resource/John_Spencer_(Scottish_footballer)> . ?x onto:homeStadium ?uri . }