Database: food_inspection_2
Question: How many grocery stores paid $250 fine upon their inspection?
SQL: SELECT COUNT(DISTINCT T1.license_no) FROM establishment AS T1 INNER JOIN inspection AS T2 ON T1.license_no = T2.license_no INNER JOIN violation AS T3 ON T2.inspection_id = T3.inspection_id WHERE T1.facility_type = 'Grocery Store' AND T3.fine = 250