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.
['4411', 'V', '5013', 'j', '7023', '2555', '443', 'o', '6301', 'r', '485', 'J', 'B', 's', 'p', 'N', '3273', '6825', '4597', 'b']