-- Database schema
| cites : cited_paper_id [ TEXT ] , citing_paper_id [ TEXT ] | paper : paper_id [ TEXT ] primary_key , class_label [ TEXT ] | content : paper_id [ TEXT ] content.paper_id = paper.paper_id , word_cited_id [ TEXT ] |
-- -- How many papers were cited by schmidt99advanced cited word3555?

SELECT COUNT(T2.paper_id) FROM cites AS T1 INNER JOIN content AS T2 ON T1.cited_paper_id = T2.paper_id WHERE T1.citing_paper_id = 'schmidt99advanced' AND T2.word_cited_id = 'word3555';