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: ['9403', 'u', '4159', 'w', '3467']
Example Output: 17029

Example Input: ['O', '6337', 'j', '6009', 'z']
Example Output: 12346

Example Input: ['7335', '813', '6461', '8903', '3709', 'V', 'G', 'I', 'P', 'p', 's', 'v', 'R', '4697', '4263', '9897']
Example Output:
46078