Database: academic
Question: return me the number of papers written by " H. V. Jagadish " , " Yunyao Li " , and " Cong Yu " .
SQL:
SELECT COUNT ( DISTINCT t7.title ) FROM writes AS t4 JOIN author AS t2 ON t4.aid  =  t2.aid JOIN publication AS t7 ON t4.pid  =  t7.pid JOIN writes AS t5 ON t5.pid  =  t7.pid JOIN writes AS t6 ON t6.pid  =  t7.pid JOIN author AS t1 ON t5.aid  =  t1.aid JOIN author AS t3 ON t6.aid  =  t3.aid WHERE t2.name  =  "Cong Yu" AND t1.name  =  "H. V. Jagadish" AND t3.name  =  "Yunyao Li";