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', '711', '5817', 'i', '7929', '1431', '927', 'C', '8759', '5221', 'I', 'K', 'q', '9017', 'x', '5453', 'h', '1351', '6245']