How many {tributary} are for {Orinoco} ?
How many tributaries does Orinoco have?
SELECT (COUNT(?obj) AS ?value ) { wd:Q131792 wdt:P974 ?obj }
SELECT (COUNT(?obj) AS ?objs ) {
?statement <http://www.w3.org/1999/02/22-rdf-syntax-ns#subject> <http://wikidata.dbpedia.org/resource/Q131792> .
?statement <http://www.w3.org/1999/02/22-rdf-syntax-ns#predicate> <http://www.wikidata.org/entity/P974> .
?statement <http://www.w3.org/1999/02/22-rdf-syntax-ns#object> ?obj .
} 

Give the number of tributaries of Orinoco ?