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.
['5629', 'v', '5041', 'f', '5259', '9573', '1563', '3659', 'r', 'b', 'h', '717', '1251', '6957', 'Q', 'z', '1875', '9153']