In this task, you are given an input list A. You need to find all the elements of the list that are numbers and calculate their sum.
['A', 'W', 'T', 'D', 'l', 'N', 'Z', 'B', '8293', 'm', 'Z', 'J', 'v', '8931', '9621', '5561', '7835', '6019', '1479']