Using an Action to format Title

I am trying to write an Action that will output the Title format

01a, 01b, 01c ... 01x,01y

Where 01 is the disc number and the letter increments.

I am using
$num(%discnumber%,2)$char($add(96,$num(%_counter%)))

Since %_counter% always starts at 1. I add 96 to the %_counter% to get 97 which is the decimal equivalent for the letter "a" in Basic Latin Unicode. The next loop should give 98 or "b" and so on.

The output I get is 01' no matter the number of loops
The $char function sees only the 96 and not the $add function.

Either I have a syntax error or I am trying to do something in the wrong manner

Thanks for the help

Try this:
$num(%discnumber%,2)$char($add(96,%_counter%))

That does the trick. Well it was a syntax error. Well more for me learn.

Thanks.