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.
['i', '1337', 'V', 'W', '7515', '2625', 'a', 'v', 'O', 'a', 't', 'i', 'g', 'H', '2155', '4869', 'e', 'd', '1039']