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: ['4701', 'b', 'i', 'B', 'z', '7837', 'W']
Example Output: 12538

Example Input: ['4607', 'T', 'a', '6077', 'c', '4761']
Example Output: 15445

Example Input: ['4015', '1565', '7231']
Example Output:
12811