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.

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


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


[Q]: ['4029', '3607', 'q', '6535']
[A]:
14171