Database: scholar
Question: How many papers are about deep learning ?
SQL:
SELECT DISTINCT COUNT ( DISTINCT t3.paperid ) FROM paperkeyphrase AS t2 JOIN keyphrase AS t1 ON t2.keyphraseid  =  t1.keyphraseid JOIN paper AS t3 ON t3.paperid  =  t2.paperid WHERE t1.keyphrasename  =  "deep learning";