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.
['T', 'B', 'n', '1737', '6049', 'D', '1905', 'B', '7005', 'x', '7727', '6221', 'D', 'p', 'E', 'h', 'S', 'k']