How many {father} are to/by {Victor Hugo} ?
How many children does Victor Hugo have?
Victor Hugo is the father to how many individuals?
SELECT ( COUNT ( ?n ) AS ?k ) { ?n property:father resource:Victor_Hugo }
SELECT (COUNT(?sub) AS ?subs ) {
?statement <http://www.w3.org/1999/02/22-rdf-syntax-ns#subject> ?sub .
?statement <http://www.w3.org/1999/02/22-rdf-syntax-ns#predicate> <http://www.wikidata.org/entity/P22> .
?statement <http://www.w3.org/1999/02/22-rdf-syntax-ns#object> http://wikidata.dbpedia.org/resource/Q535 .
} 

SELECT (COUNT(?sub) AS ?value ) { ?sub wdt:P22 wd:Q535 }
4