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.
['2095', '3929', 'D', 'd', '5763', 'd', '6445', '4613', 'a', '7649', '8817', '1473', '8403', 'Z', 'h', 'S', 'i', 'T', '7931']