Below is an instruction that describes a task. Write a response that appropriately completes the request.

### Instruction:
In grid 15, how many laps were there before ending with a time of exhaust?

### Inputs:
table_name: table, columns: ['Driver', 'Constructor', 'Laps', 'Time/Retired', 'Grid']

### Response:
SELECT SUM Laps FROM table WHERE Time/Retired = exhaust AND Grid < 15