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.
['G', 'M', 'G', 'q', '8151', '4351', 'D', 'E', 'f', 'N', '6497', 'Y', '1117', '7971', '5669', 'u', '9179', '8177']