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: Please show the most common type of ships. | mission : mission_id , ship_id , code , launched_year , location , speed_knots , fate | ship : ship_id , name , type , nationality , tonnage | mission.ship_id = ship.ship_id | 

### Response:

select _ from _ group by _ order by count ( _ ) desc limit _ | select type from ship group by type order by count ( * ) desc limit 1