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 Q]: ['7959', '1345', '4605', '6453', 'Q']
[EX A]: 20362

[EX Q]: ['1057', '3937']
[EX A]: 4994

[EX Q]: ['L', '4623', '4733', 'N', 'k', 'G', 'M', 'z', 'f', '7423', 'e', 'H', '9547', 'K', '2093', 'W', 'y']
[EX A]:
28419

