Find the name of the employees with a particular letter

Question

I'm having the schemas like:

Employee (Empno, Empname, City)
Project (Pno, Pname)
Part (Partno, Partname, Color)
Use (Pno, Partno)
Works (Empno, Pno)

From these schemas I had created a sample tables:

The goal is to find the names of the projects where no employees are working whose name starts with 'S'

I'm using ORACLE 11g Express Edition. Here I used this query : For Names:

Select DISTINCT Pname FROM
(
SELECT w.Empno, p.Pno, p.Pname, e.Empname
FROM Works w
LEFT JOIN Project p ON w.Pno=p.Pno
LEFT JOIN Employee e ON e.Empno=w.Empno
)
WHERE Empname not like 'S%';