Question: For how many PMs did the politician work, whose successor was Kingsley Wood?
SPARQL:
SELECT DISTINCT COUNT(?uri) WHERE { <http://dbpedia.org/resource/Kingsley_Wood> <http://dbpedia.org/ontology/successor> ?x . ?x <http://dbpedia.org/property/primeminister> ?uri  . ?x <http://www.w3.org/1999/02/22-rdf-syntax-ns#type> <http://dbpedia.org/ontology/OfficeHolder>}