Group By For Different Column Values

I have 2 tables which have the data as follows:

A:
Id Reason Amount Subject RecordNo
1 Gift 100 first 11
2 Gift Reason 200 second 12
3 Gift Reason 100 first 11

The result that I want is :

Reason Amount Subject
ALL 200 first
i used the following query

select
case when Grouping(B.Subject) <> '' then 'ALL' else B.Subject End as Subject ,
case when Grouping(B.reason) <> '' then 'ALL' else B.Reason END as Reason,
SUM(B.amount) as amount
from B
where B.RecordNo = 11
group by grouping sets (B.Reason,B.Subject)

but it's giving me 3 rows in return.

I want only one summation row. How can i get that?