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.
['773', '8561', '4361', '413', 'z', 'Q', '1753', 'q', '1647', 'q', '3941', '2729', 'F', '6589', 'M', '589', 'I', '9289']