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: ['Y', '8169', '9067']
Example Output: 17236

Example Input: ['Y', '9053', 'N', '6921']
Example Output: 15974

Example Input: ['7709', 'c', 'c', '1745', 'H', 'A', '1881', '5693', 'O', '793', '8807', '8415', '4491', '7299']
Example Output:
46833