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.
['N', 'i', 'o', 'f', 't', 'w', '9443', 'a', '9845', 'w', 'f', 'Q', '9395', '7933', '9683', 's', '4759', 'o', 'D']