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.
['3565', 'M', 'i', '6283', '7107', '8053', 'u', '7911', '5709', '8417', 'C', '1521', '3561', '9801', '6431', 'c', '1301']