Database: academic
Question: return me the number of the papers of " H. V. Jagadish " containing keyword " User Study " .
SQL: select count ( distinct t5.title ) from publication_keyword as t3 join keyword as t1 on t3.kid  =  t1.kid join publication as t5 on t5.pid  =  t3.pid join writes as t4 on t4.pid  =  t5.pid join author as t2 on t4.aid  =  t2.aid where t2.name  =  "h. v. jagadish" and t1.keyword  =  "user study";