How many {feast day} are to/by {Pentecost} ?
How many feasts days do Pentacostals observe?
How many feast days are done by Pentecost?
SELECT ( COUNT ( ?t ) AS ?k ) { ?t property:feast_day resource:Pentecost }
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/P841> .
?statement <http://www.w3.org/1999/02/22-rdf-syntax-ns#object> http://wikidata.dbpedia.org/resource/Q39864 .
} 

SELECT (COUNT(?sub) AS ?value ) { ?sub wdt:P841 wd:Q39864 }
7