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: What is the count of states with college students playing in the mid position but not as goalies? | college : cname , state , enr | player : pid , pname , ycard , hs | tryout : pid , cname , ppos , decision | tryout.cname = college.cname | tryout.pid = player.pid | 

### Response:

select count ( _ ) from ( select _ from _ where _ except select _ from _ where _ ) | select count ( * ) from ( select college.state from college join tryout on college.cname = tryout.cname where tryout.ppos = 'mid' except select college.state from college join tryout on college.cname = tryout.cname where tryout.ppos = 'goalie' )