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.
['1055', 'i', '8787', 'H', 'K', '9065', '8499', 'l', 'r', 'm', 'd', '8937', 'z', '1399', '8429', 'w', 'L', '8323', 'Q']