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.

Example Input: ['p', '4689']
Example Output: 4689

Example Input: ['E', 'y']
Example Output: 0

Example Input: ['2857', '9765', 'I', 'j', 'L', 'p', 'V', '6089', 'K']
Example Output:
18711