user: Question: What is the grid total that had a retired for engine, teo fabi driving, and under 39 laps?
Columns: ['Driver', 'Constructor', 'Laps', 'Time/Retired', 'Grid']
Types: ['text', 'text', 'real', 'text', 'real']
Sample row: ['Alain Prost', 'McLaren - TAG', 60.0, '1:32:28.408', 4.0]
SQL:

assistant: SELECT SUM("Grid") FROM "Table" WHERE "Time/Retired" = 'engine' AND "Driver" = 'teo fabi' AND "Laps" < 39.0;