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.
['K', 'M', 'j', 's', '2231', '7241', 'E', '1647', 'G', '1471', '5419', '5147', '7693', '9261', 'X', '2161', 'R', '1887', 'U', '1269']