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.
['6387', '3671', 'T', '4435', '315', '7955', 'F', '2009', 'K', 'B', '1023', 'h', 'D', 'G', '4753', '7889', '4087', 'd', 'B']