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.
['E', 'Y', '4061', '4801', 'S', 'T', 'S', 't', '2167', 't', 'y', 'N', '6935', '2025', 'T', '731', 'G', 'u', 'o', 'C']