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.

Ex Input:
['4949', '2459', 'n', 'f', 'n', 'v', '8421', '1519', '4859', 'c', '9923', '2829', 'K', '4937', 'W', 'R']

Ex Output:
39896


Ex Input:
['q', '5151', 'R', '441']

Ex Output:
5592


Ex Input:
['H', '8733', '2039', 'a', 'L', 'N', '2285', '1921', '5309', 'i', 'u', '4539', '6013', '5393', '1499', 'Z', 'l', 'H', 'X', 'k']

Ex Output:

37731