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: ['Q', '8841', 'H', 'v', '2435', '8221', '807', 'P', '2247', 'M', '4609', '5657', 'k', '2807', 'j', '8451']
Example Output: 44075

Example Input: ['2097', '7815', 'f', '1705', '7553', 'C', 'n', '7091', '1253', 'z', '9229', 'H', 'N', '6481', 'H', 'M', 'G', '4527', '8537']
Example Output: 56288

Example Input: ['n', 'P', '1101', '1443', '1823']
Example Output:
4367