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]: ['I', '7815']
[EX A]: 7815

[EX Q]: ['j', '6731', 'h', 'G', 'F', '6899', '4317', 'm', '9491', 'l', '971']
[EX A]: 28409

[EX Q]: ['C', 'v']
[EX A]:
0