return me the number of papers which contain the keyword " Natural Language " .
SELECT COUNT ( DISTINCT t3.title ) FROM publication_keyword AS t2 JOIN keyword AS t1 ON t2.kid  =  t1.kid JOIN publication AS t3 ON t3.pid  =  t2.pid WHERE t1.keyword  =  "Natural Language";
SELECT COUNT ( DISTINCT t3.title ) FROM publication_keyword AS t2 JOIN keyword AS t1 ON t2.kid  =  t1.kid JOIN publication AS t3 ON t3.pid  =  t2.pid WHERE t1.keyword  =  "Natural Language";
[{'COUNT ( DISTINCT t3.title )': 0}]