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]: ['291', 'R', 'N', '983', '2879', 'C', '3797', '4837', '793', '5489', 'k', '535', 'L', '3605', 's', '3701', 'U', '4399', '2489', '4739']
[EX A]: 38537

[EX Q]: ['w', '4181', 'g', 'j', '1823', 'q', 'i', '709']
[EX A]: 6713

[EX Q]: ['5537', '307']
[EX A]:
5844