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.
['t', 'f', '761', '7309', '1089', '5959', 'w', '805', '1743', 'E', '219', 'U', 'N', 'g', 'p', 'p', 'd', '1691', 'Z']