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: ['I', '7815']
Example Output: 7815

Example Input: ['b', '5689', '119', 'p', 'P', 'J', 'w', 'm', '7397', 'Y', '447', 'O', 'p', '319', 'H', 'U']
Example Output: 13971

Example Input: ['6015', 'G', 'Z', 'l', '2699', 'C', 'z', '6435', '4369', 'i', '5473', '1897']
Example Output:
26888