Count same values within one cell

Hi all :wave:

Not sure if this has already been discussed:
I have in a column this values:
“a,a,a,b,b,c,c,c,b,b,a”

Now I want to know the 1-2 highest counts, in this case “a,b” as a result (as 4times a, 4 times b, 3 times c)

How should I do this in a formula?