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.
['j', 'm', 'x', 'T', '2969', '3735', 'G', 'r', 'a', 'y', 'g', '8501', 'p', 'a', '2583', '5933', '3257', '1329']