How many {health specialty} are to/by {hematology} ?
How many health specialties are like hematology?
SELECT (COUNT(?sub) AS ?value ) { ?sub wdt:P1995 wd:Q103824 }
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/P1995> .
?statement <http://www.w3.org/1999/02/22-rdf-syntax-ns#object> http://wikidata.dbpedia.org/resource/Q103824 .
} 

Total health specialties like hematology