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]: ['R', 'C', 'S', 'x', '1529', 'r']
[A]: 1529


[Q]: ['Z', '6245', 'N', '1403', 'b']
[A]: 7648


[Q]: ['3281', 'f', 'j', '2911', 'c']
[A]:
6192