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]: ['3683', 'U', 'x', '313', 'n', '3837', '3299', '2081', '2773', 'r', 'O', '257', '6647', '585', 'o']
[EX A]: 23475

[EX Q]: ['3839', 'D', '4741', 'L']
[EX A]: 8580

[EX Q]: ['K', 'j', 'g', 'N', 'M', '1643', '3015', 'n', '7931', '4701', 'C', '2579', '1421', 'D', 'I', 'P', 'k', 's', 'o', '5433']
[EX A]:
26723