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:
['57', '9977', '2657', 'p', '9573', '7745', '4755', 'U']

Ex Output:
34764


Ex Input:
['7771', 'g']

Ex Output:
7771


Ex Input:
['P', '7939', 'V', 'Q']

Ex Output:

7939