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.

['w', '2281', '8651', '2203', 'q', 'n', '4253']
17388

['135', 'a', 'X', '8067', '8447', '4009', '4221', 'o', 'A', 'x']
24879

['L', '7083', 'c', '4759', '1297', 'a', '2647', '4267', '5539', 'U', '8083']

33675