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: ['K', '4403', 'a', '3881', '4139', 'w', '1861', 'G']
Example Output: 14284

Example Input: ['v', 't', 'a', 'r', 'O', 'I']
Example Output: 0

Example Input: ['Z', '5129', 'E', 'I']
Example Output:
5129