user: Question: What is the grid total associated with 18 laps?
Columns: ['Rider', 'Manufacturer', 'Laps', 'Time/Retired', 'Grid']
Types: ['text', 'text', 'real', 'text', 'real']
Sample row: ['Héctor Faubel', 'Aprilia', 19.0, '40:57.408', 2.0]
SQL:

assistant: SELECT SUM("Grid") FROM "Table" WHERE "Laps" = 18.0;