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.
['Y', 'L', 'u', 'x', 'K', 'W', '835', '8113', '2213', 'b', 'p', 'w', '3925', 'M', '9679', '365', 'K', 'y']