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.
['8337', 'R', 'd', 'N', 'm', '8861', 'z', 'e', 'P', '3927', '3953', 'A', '7657', 'S', '2311', 'T', '5983', '8355']