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', 'O', '2885', '703', 'y', '589', '1471', '5505', 'g', '6077', '7689', 'T', '8559', 'O', '4655', 'N', '521', '1569', 'A', 'z']