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

### Instruction:
What is the highest numbered nightly rank for any episode?

### Inputs:
table_name: table, columns: ['Order', 'Episode', 'Original airdate', 'Timeslot', 'Viewers (100000s)', 'Nightly rank', 'Weekly rank']

### Response:
SELECT MAX Nightly rank FROM table