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: ['G', 'Z', '4819', '9763', '9987']
Example Output: 24569

Example Input: ['R', 'J', 'z', 'o', '1121', '7247', '8987', 'u']
Example Output: 17355

Example Input: ['G', 'R', 'e', 'U', '1113']
Example Output:
1113