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: ['n', '6729', 'p', 'D', 'o', '1213', 'e', '6951', '2341', '9997', 'e', 'M', 'x', 'R']
Example Output: 27231

Example Input: ['2485', 'Q', 'G', '5533', 'Y', '21', 'D', 'S']
Example Output: 8039

Example Input: ['1027', '8353', '9525']
Example Output:
18905