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.

Ex Input:
['R', 'C', 'S', 'x', '1529', 'r']

Ex Output:
1529


Ex Input:
['7459', '491', '7823', '6965', 'H', '109', 'R', 't', '3959', '2821', 'R', '2807', 'o', 'v', '1305', 'a', '1411', 'r', '3669']

Ex Output:
38819


Ex Input:
['l', '3199', '8577']

Ex Output:

11776


