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']
Example Output: 0

Example Input: ['6051', '5303', '1509', '2797', 'Z', '4777', '721', '8563', 'K', '63', '9115', 'd', '7305', '9743', '7409']
Example Output: 63356

Example Input: ['H', 'R', '5783', 'z', 'Y', '1249', '2531', 'U', '4495']
Example Output:
14058