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.
['M', 'I', '8833', '8641', 'Z', 'h', '3907', '1737', '7693', 'v', '6273', '3163', '4529', 'a', '5465', 'O', '4293', 'c', '2313']