CREATE TABLE table_54813 ("Driver" TEXT, "Constructor" TEXT, "Laps" FLOAT, "Time/Retired" TEXT, "Grid" FLOAT)

What is the sum grid number when the driver was Luciano Burti?
SELECT COUNT("Grid") FROM table_54813 WHERE "Driver" = 'luciano burti'
SELECT COUNT("Grid") FROM "table_54813" WHERE "Driver" = 'luciano burti'