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.
['9883', 'H', 'J', 'j', 'O', 'E', 't', 'y', '3809', '2403', 'S', 'g', 'k', '6731', '1501', 'h', '1051', 's', '3183']