CREATE TABLE table_name_44 (grid INTEGER, rider VARCHAR(255), manufacturer VARCHAR(255), laps VARCHAR(255))
What is the grid number of Sandro Cortese, who has Aprilia as the manufacturer and less than 19 laps?
    
SQL: SELECT SUM(grid) FROM table_name_44 WHERE manufacturer = "aprilia" AND laps < 19 AND rider = "sandro cortese"