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.
['8397', 'H', 'k', '441', '2017', '5121', 'h', 'F', 's', 'T', 'H', 'i', '2747', '2625', 'f', 't', 'F', '8369']