SQLite "appear the amount of courses for every student whether he is in Attends or not" sql query

I have an ER Diagram as shown below

for every student I want to appear all courses that addends. So I use query

select studentId,course.courseCode
from student natural left outer join attends
natural left outer join course

which gives me all results in right way

now I want to appear the total amount of courses that a student attends and I am using this query

select studentId,
  (select count(attends.courseCode) 
  from attends natural left outer join student
  )as 'amount'
from student

but I am having this result

How am I supposed to appear the real amount of courses for every student whether he is in Attends or not? That is, a 0 for studentId 6,7,8 and a 2 for studentId 17 etc. Thank you in advance

PS1: If you want more of my tables, please let me know.

PS2: I was not sure about the title. If you find that another title fits better, please suggest