with get_A as
(
select
A.hacker_id, count(A.Challenge_Id) Total_no_of_challenges
from 
submissions A 
join challenges B on A.Challenge_Id=B.Challenge_Id 
join difficulty C on B.difficulty_level=C.difficulty_level 
where A.score = C.score
group by A.hacker_id
having count(A.Challenge_Id)>1
)
select x.hacker_id, y.name
from get_A x join hackers y on x.hacker_id=y.hacker_id
order by x.Total_no_of_challenges desc, x.hacker_id;