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.
['1307', 'm', '2333', 'Q', '8133', '1351', '3533', '5937', '6597', '3367', 'u', 'F', 'P', '1653', '3395', 'n', 't', 'v']