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: ['v', '9511', 'f', 'q']
Example Output: 9511

Example Input: ['2913', 'b', 'j', '7591', 'O', 's', '5589', '4995', '7503', 'U', 'S', 'C', '6797']
Example Output: 35388

Example Input: ['B', '7887', 'a', 'S', '1873', 's']
Example Output:
9760