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: ['Y', '8169', '9067']
Example Output: 17236

Example Input: ['4607', 'T', 'a', '6077', 'c', '4761']
Example Output: 15445

Example Input: ['5897', '739', '4025', '9065', '2235']
Example Output:
21961