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]: ['d', '4553']
[A]: 4553


[Q]: ['4869', 'L']
[A]: 4869


[Q]: ['4257', '91', 'g', 'q', '5463', 'R', '679', '4327', '8261', '7063', 'c', '6439', '2721', 'M', 'z', '6921', '4493']
[A]:
50715