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: ['R', '3361', 'c', 'S', 'g', '3829', '7347', '6633', 'e', '9227']
Example Output: 30397

Example Input: ['M', '9387', '7125', 'c', '1295', 'X', 'l', '9867']
Example Output: 27674

Example Input: ['Z', 'Z']
Example Output:
0