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: ['X', '6189', '5435', 'y', '8931', '8987', 'F', '8377', 'k', '8631', '8717', 'q', '2923', 'g', '7225', 'j']
Example Output: 65415

Example Input: ['k', 'a']
Example Output: 0

Example Input: ['8633', '7347', '3783', 'h', '3133', '6989', 'E', 'j', '5945', '6891', '4539', 'Y', 'm', 'n', 'P', 'Q', '1651']
Example Output:
48911