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.
['9819', '7503', 'j', 'g', 'v', 't', 'e', 'w', 'o', '6775', '1873', 'J', '6263', '8315', '4041', '3013', '4569', '3575']