How many {vessel} are to/by {Soyuz} ?
How many vessels are to be voyage ?
SELECT (COUNT(?sub) AS ?value ) { ?sub wdt:P1876 wd:Q579421 }
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/P1876> .
?statement <http://www.w3.org/1999/02/22-rdf-syntax-ns#object> http://wikidata.dbpedia.org/resource/Q579421 .
} 

how many vessels to voyage?