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.
['Q', 'd', '6537', '3505', '6897', 'm', '6123', '7157', 'h', 'J', 'X', 'Y', 'L', '2967', '501', '7289', 'e', 'S', 'P']