user: Question: What is the sum grid number when the driver was luciano burti?
Columns: ['Driver', 'Constructor', 'Laps', 'Time/Retired', 'Grid']
Types: ['text', 'text', 'real', 'text', 'real']
Sample row: ['Michael Schumacher', 'Ferrari', 55.0, '1:47:34.801', 1.0]
SQL:

assistant: SELECT SUM("Grid") FROM "Table" WHERE "Driver" = 'luciano burti';