How many papers were presented at 'ECSQARU' in 2003?
Papers refers to Paper.Id; ECSQARU is the ShortName of the conference; 2003 refers to Year = '2003'
SELECT COUNT(T1.Id) FROM Paper AS T1 INNER JOIN Conference AS T2 ON T1.ConferenceId = T2.Id WHERE T2.ShortName = 'ECSQARU' AND T1.Year = '2003'