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]: ['D', 'm', 'P', '2433', '6731']
[EX A]: 9164

[EX Q]: ['t', '7469', 'Y', 'N', '8137']
[EX A]: 15606

[EX Q]: ['3305', '9027', 's', '8457']
[EX A]:
20789