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.

['4869', 'L']
4869

['Z', '4157', '5185', 'U', 'i', '1115', 'A', '7427', '3313', 'S']
21197

['s', '8105', '3517']

11622