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: ['3469', 'n', '5561', '8597', '921', '4737', 'r', 'P', '7127', '3651', 'D', '1703', 'y']
Example Output: 35766

Example Input: ['Q', '2271', '1803', '2363']
Example Output: 6437

Example Input: ['Z', '7939', 'N', '1135', '4495', 'a', 'v', '1767', '7739', '3443', 'o', 'b', 'Z', 'B', 'L', 'e', '9071', '9787']
Example Output:
45376