-- Database schema
| list : LastName [ TEXT ] primary_key , FirstName [ TEXT ] , Grade [ INT ] , Classroom [ INT ] | teachers : LastName [ TEXT ] primary_key , FirstName [ TEXT ] , Classroom [ INT ] |
-- -- For each grade 0 classroom, return the classroom number and the count of students.

SELECT classroom ,  count(*) FROM list WHERE grade  =  "0" GROUP BY classroom;