Below is an instruction that describes a task, paired with an input that provides further context. Write a response that appropriately completes the request.

### Instruction:

Convert text to sql: Find the captain rank that has some captains in both Cutter and Armed schooner classes. | captain : captain_id , name , ship_id , age , class , rank | ship : ship_id , name , type , built_year , class , flag | captain.ship_id = ship.ship_id | 

### Response:

select _ from _ where _ intersect select _ from _ where _ | select rank from captain where class = 'Cutter' intersect select rank from captain where class = 'Armed schooner'