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.
['1595', '5861', 'g', 'H', 'h', '1449', '1993', '3569', 'M', 'o', '6587', 'w', 'y', '7063', '8723', '3729', 'Q']