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.
['F', 'g', 'O', 'n', 'J', 'c', 'l', 'Q', 'V', '3659', 'D', '7209', 'x', 'X', 'n', '1315', '9155', 'l', 'o', 'x']