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.
['M', '5201', '2787', 'z', '9465', 'X', 'X', '4017', '8305', 'y', '6897', 'y', '6045', '9863', 's', 'd', '3611', 'l', 'd']