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:
['2087', '8171', 'c', 'd', 'a', '5621', 'n']

Ex Output:
15879


Ex Input:
['507', 'P', '9697', 'u', '5057']

Ex Output:
15261


Ex Input:
['J', '3909', '9609', 'I', 'n', '1595', '4159', '1181', '9847', '9855', 'b', 'o', 'I', 'k', '7759', '7921', '817']

Ex Output:

56652