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.
['1583', '3293', 'z', '1039', '5179', '535', '1127', '3271', 'q', 'M', '4487', 'D', '5083', 'R', 'r', 'L', '215', 'H']