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: ['7973', 'J', '9035', 'H', '4051', '2661', 's', 'z', '8225', 'M', '4153']
Example Output: 36098

Example Input: ['D', 'm', 'P', '2433', '6731']
Example Output: 9164

Example Input: ['m', 'g', '7251', '5873', '59', '7345']
Example Output:
20528