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: ['6787', 'W', 'I', '4929', 'j', 'I', '3487', 'F', '3927', 'Q', 's', 'X', '9939', 'n']
Example Output: 29069

Example Input: ['w', 'I', 't', '813', 'K', '5785']
Example Output: 6598

Example Input: ['1883', '8749', 'z', 'g', '5113', 'x', 'q']
Example Output:
15745