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]: ['Q', '8317', '8989']
[A]: 17306


[Q]: ['d', '5571', '6455', '4287', 'I', 'U', 'M', '8303', '8893']
[A]: 33509


[Q]: ['4489', 'n', 'V']
[A]:
4489