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: ['V', '8137', 'b', 'k', '2081', 'L', '9733', '7525', 'D', '2381', 'O']
Example Output: 29857

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

Example Input: ['Q', '9979', '5845']
Example Output:
15824