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', 'X', 'd', 'N', '1877', '2865', 'M', '1249', '9385', 'v', 'o', 'P', 'P', '6029']
Example Output: 21405

Example Input: ['Y', '263', '641', '1163', 'p', 'r', 'L', '4425', 'C', '7585']
Example Output: 14077

Example Input: ['775', 'k', 'U', '9141', '1639', '8303']
Example Output:
19858