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.

['u', 'B', '2509', 'U', 'R', '7497', '1897', '8697', 't', 'W', '1021', '7937', 'F', 'g', '6901', 'I', '2957']
39416

['z', 'T', 'Y', 's', 'j', '585', '7833', '2601', '8057', 'S', '7037', '5799', '4477', '5377', '6301', 'P', 'm', '9431', 'f']
57498

['z', 'f', 'Z', '5905', 'v', 'p', '37', '5413', '5267', 'X', '8633', 'm', 'I', '5709', '3417', 'p', 'l', 's', '8241', 'Z']
42622