How many papers has Christopher D. Manning published ?
SELECT DISTINCT COUNT ( DISTINCT t2.paperid ) FROM writes AS t2 JOIN author AS t1 ON t2.authorid  =  t1.authorid WHERE t1.authorname  =  "Christopher D. Manning";
SELECT DISTINCT COUNT ( DISTINCT t2.paperid ) FROM writes AS t2 JOIN author AS t1 ON t2.authorid  =  t1.authorid WHERE t1.authorname  =  "Christopher D. Manning";
[{'COUNT ( DISTINCT t2.paperid )': 0}]