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.
['W', 'T', 'g', 'V', 'o', '3073', '5709', 's', '4913', 'C', '379', '4173', '6585', 'Z', 'X', '1973', 'v', 'y', '1135', 'm']