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.
['1265', 'H', 'L', '5295', 'l', 'o', '6375', 'S', 'L', 'h', 'M', 'G', 'w', 'T', 'k', '4071', '9525', '9803']