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: ['4975', 'M', 'C', 'D', 't', 'i', 't', 'L']
Example Output: 4975

Example Input: ['u', 'i', 'z', 't', '9617', 'd', '3255', 'w', 'S', '3041', '7451']
Example Output: 23364

Example Input: ['9117', '533', 'x', '7235', 'o', '5629', '1823', '1987', '7805', '6283', '2861']
Example Output:
43273