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.
['z', 'f', 'Z', '5905', 'v', 'p', '37', '5413', '5267', 'X', '8633', 'm', 'I', '5709', '3417', 'p', 'l', 's', '8241', 'Z']