How can I show letter grades (A, B, C, D) on the Y-axis of a bar chart?

Hi, I’m trying to create a bar chart where the Y-axis shows letter grades like A, B, C, D — instead of numbers like the following images

So far, I can only show the numeric Value on the chart(by matching letter grade with numeric value like A: 8, B: 6), but I’d like to visually display the letter grade instead, while still using the numeric value for sorting and height.

Is there a way to do this in Coda?

I think this can’t be done - since one of the axis need to represent a numerical value.