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

### Instruction:
What is the total launch failures when there are 4 launches, and the not usable is greater than 0?

### Inputs:
table_name: table, columns: ['Block', 'Launched', 'Operational', 'Not usable', 'Retired', 'Launch Failures']

### Response:
SELECT SUM Launch Failures FROM table WHERE Launched = 4 AND Not usable > 0