How many {parent organization} are to/by {Princeton University} ?
There are how many parent organizations at Princeton?
Princeton University has how many parent organization?
SELECT ( COUNT ( ?s ) AS ?r ) { ?s property:parent_organization resource:Princeton_University }
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/P749> .
?statement <http://www.w3.org/1999/02/22-rdf-syntax-ns#object> http://wikidata.dbpedia.org/resource/Q21578 .
} 

SELECT (COUNT(?sub) AS ?value ) { ?sub wdt:P749 wd:Q21578 }
10