Get Total of Specific Background Colored Cells

Hello,

In the attached spreadsheet, I would like to get the total of the different colored cells:

2021-04-19_13-56-53.png

I have tried using the GET.CELL(28,xxx), however, this approach cannot work because I need to have the "cell color number" appear in the respective colored cell.

How can I automatically get the total of the different colored cells in that "Total" column?

Sincerest Thanks for all your time and help!