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.
['1067', '6397', '8451', '4205', '6109', 'y', '7927', 'Y', '2761', '1147', 'p', 'c', 'q', '9137', '7615', 't', '1563', '4661', 'q']