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.
['r', '5041', 'P', 'H', '8671', '6987', '6521', '1071', 'C', 'E', '2043', '9035', '9817', '3223', 'U', 'q', 'U', 'e']