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.
['q', 'I', 'E', 'M', 'T', 'i', '8719', 'r', 'V', '9759', 'I', '1793', 'Q', 'P', '5263', 'I', 'O', '8603', 'y']