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: ['c', '7415', '6253', '4477', 't', '9449', '7733', '2325', 'Z', '5413', 'q', 'm', 'R', '8619', '7289', '857', '7273', '7425']
Example Output: 74528

Example Input: ['j', 'R', '2435']
Example Output: 2435

Example Input: ['u', 'X', 'w', '6413', '6595', 'v', 'i', '6207']
Example Output:
19215