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: ['M', 'H', 'l', 'Y', '3811', '1953', '5869', 'U']
Example Output: 11633

Example Input: ['i', 'A', 'a']
Example Output: 0

Example Input: ['2591', 'q', 'h', '5759', '6559', '311', 'T', '9013', 'b', '4253', 'M', '693', 'C', '4215', '7487', 'M', 'K', 'H']
Example Output:
40881