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: ['6551', 'm', '3941', 'F', 'K', 'u', '7981', '9581', 'X', 'M', 'N', 'e', 'G', 'i']
Example Output: 28054

Example Input: ['3145', 'C', '7725', 'k', 'z']
Example Output: 10870

Example Input: ['8091', 'P', 'O', '4869', '8881', 'z']
Example Output:
21841