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.
['83', 'k', 'p', 'o', 'b', '7819', '2089', '4141', 'c', 's', '6045', '6783', 'J', 'B', 'x', 'O', 'X', '9693']