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.
['X', '9701', 'E', '1031', '1941', 'Z', 'X', 'z', 'Z', 'V', 'S', 'q', '5693', 'w', 'W', 'i', '6191', 'U']