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.
['2933', 'k', '7063', '2851', 'w', '7095', 'M', '8363', 'y', 'T', '911', '9455', 'm', 'p', 'f', 'K', 'N', 'k', 'N', '8141']