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: ['s', '425', '6135']
Example Output: 6560

Example Input: ['K', 'p', '97', 'R', '2999', 'u', '7307', '6033', '6431', 'm', 'T']
Example Output: 22867

Example Input: ['5087', '7857', '8841', '3005', 'l', 'h', '3551', 'J', '9317', '9683', '5245', '5261', 'P', 'P', '7509', 'a', '201', 'l', '6093', '5791']
Example Output:
77441