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.
['8763', 'k', '3653', 'v', 'd', 'D', 'm', '1037', 'c', 'F', '2349', '7843', '3259', 'v', '5555', '7565', '8137', 't']