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.

['D', 'P', '9951', '2897', 'V', 'C', 'B', 'H', 'c', 'h', '2843', 'a']
15691

['9403', 'u', '4159', 'w', '3467']
17029

['k', '3883', '9281', '2519', '5033', '6649', '4423', 'L']

31788