user: Question: When driver heinz-harald frentzen has a number of laps greater than 60, what is the sum of grid?
Columns: ['Driver', 'Constructor', 'Laps', 'Time/Retired', 'Grid']
Types: ['text', 'text', 'real', 'text', 'real']
Sample row: ['Damon Hill', 'Williams - Renault', 63.0, '1:41:42.522', 4.0]
SQL:

assistant: SELECT SUM("Grid") FROM "Table" WHERE "Laps" > 60.0 AND "Driver" = 'heinz-harald frentzen';