In which year was the first paper by Okamura, Hiroyuki published?
Find the year in which Hiroyuki Okamura published their first paper.
SELECT DISTINCT MIN(xsd:integer(?answer)) AS ?answer WHERE { ?x <https://dblp.org/rdf/schema#authoredBy> <https://dblp.org/pid/85/3171> . ?x <https://dblp.org/rdf/schema#yearOfPublication> ?answer }
<https://dblp.org/pid/85/3171>