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.
['s', 'v', 'n', '6735', 'E', 'w', 'K', 'Z', 'a', '5791', 'w', 'j', '5471', '7851', '4905', '6383', 'W', '7095', 'e']