instruction:
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.
question:
['4949', '2459', 'n', 'f', 'n', 'v', '8421', '1519', '4859', 'c', '9923', '2829', 'K', '4937', 'W', 'R']
answer:
39896


question:
['z', 'c', 'E', 'Q', '1839', 'g', 'X', 'c', '291', 'c', 'w', 'e', '5957', 'X', '6471', 'A', '8359', 'y', '3611', '5417']
answer:
31945


question:
['2017', '9925', 'm', '6189', 'R', '5251', 'l']
answer:

23382