Sum ONLY for distinct rows

[Test_Analytics]

Hi, I have a table like this.

Batch	Student
A	1
A	1
B	2
B	2
C	2
C	2
C	2

I want to show a score card showing 'Sum of students across all distinct batches', i.e. 1 + 2 + 2 = 5. The normal sum function gives me 12. I want to sum only for distinct batches, i.e. A -> 1, B -> 2, C->2.

Is there a way to do this on Looker Dashboard, without having to create a separate pivot/group by table?

Will be grateful for any help.