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: ['a', 'm', '3205', '1869', '1117', 'K', '5785']
Example Output: 11976

Example Input: ['8743', 'Y', 'O', '8265', '1029', '5689', 'F', 'j', 'Z', 'i', 'S', '1285', '737']
Example Output: 25748

Example Input: ['139', 'q', '4941', '3551', 'C']
Example Output:
8631