Question: How many scientists graduated from an Ivy League university?
SPARQL query:
PREFIX res: <http://dbpedia.org/resource/>
PREFIX onto: <http://dbpedia.org/ontology/> 
SELECT DISTINCT count (?uri)
WHERE {
  ?uri rdf:type onto:Scientist .
  ?uri onto:almaMater ?university .
	?university onto:affiliation res:Ivy_League .
}