Question: How many 'blue' attribute classes are there on image ID 2355735?
SQL: SELECT COUNT(T1.ATT_CLASS) FROM ATT_CLASSES AS T1 INNER JOIN IMG_OBJ_ATT AS T2 ON T1.ATT_CLASS_ID = T2.ATT_CLASS_ID WHERE T2.IMG_ID = 2355735 AND T1.ATT_CLASS = 'blue'