Top X values from column per day

Hi all,

Hoping you might be able to help here. Seems relatively simple, but struggling to get the desired result.

I have the below table and what I'd like to produce is a chart showing the sum of the top 2 classes per day. The top 2 on any day could be between any class.

So the first would be 10/06/2018; 18,391(a+b), 11/06/2018; 16,317 (a+c) and so on.

For some reason using a Top N visual filter won't work.

Thanks in advance
Andy

Date Class Amount
10/06/2018 a 503
10/06/2018 b 895
10/06/2018 c 7,358
10/06/2018 d 750
10/06/2018 e 596
11/06/2018 a 8,085
11/06/2018 b 6,617
11/06/2018 c 4,339
11/06/2018 d 1,609
11/06/2018 e 4,362
12/06/2018 a 1,072
12/06/2018 b 3,293
12/06/2018 c 4,213
12/06/2018 d 1,083
12/06/2018 e 9,347