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.
['B', 'q', '8537', '6949', 'o', '4303', 'i', '435', 'x', 'w', 'O', '4235', 'l', '1737', '8899', '7659', 'F', '7055', 'l', '9827']