Below is the list of tables from the database along with their columns and datatype. Need to generate an accurate SQL query for the question.
Only use the columns present in the respective table. Only use the columns which are required to generate the SQL query. Only use table joins if required and not otherwise.

### Tables ###
TABLE: CREATE TABLE assignedto ( scientist number, project text )
TABLE: CREATE TABLE scientists ( ssn number, name text )
TABLE: CREATE TABLE projects ( code text, name text, hours number )

### Question ###
Find the number of scientists involved for the projects that require more than 300 hours.

### Accurate SQL ###

SELECT COUNT(*), T1.name FROM projects AS T1 JOIN assignedto AS T2 ON T1.code = T2.project WHERE T1.hours > 300 GROUP BY T1.name