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: ['3683', 'U', 'x', '313', 'n', '3837', '3299', '2081', '2773', 'r', 'O', '257', '6647', '585', 'o']
Example Output: 23475

Example Input: ['6217', 'A', '1925', 'o', '1433']
Example Output: 9575

Example Input: ['R', '5379', '5571', 'h', '1881', '7879', '7117', 'Z', '8427', 'R', 'J', 'H', 'h', '5153', 's', 'Q', 'F', '2977', '4039']
Example Output:
48423