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.
['E', 'w', 'h', 'S', '259', 'U', '1429', '919', 'D', '5609', '7377', '7601', 'O', 'W', '43', '4571', '5059', '3267', '3129', 'y']