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.
['9757', 'b', 'f', 'f', 'N', '4243', '1253', 'b', 'v', 'h', '7577', 'X', '8095', 'M', 'D', '7423', 'u']