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.
--------
Question: ['135', 'a', 'X', '8067', '8447', '4009', '4221', 'o', 'A', 'x']

Answer: 24879


Question: ['X', '6189', '5435', 'y', '8931', '8987', 'F', '8377', 'k', '8631', '8717', 'q', '2923', 'g', '7225', 'j']

Answer: 65415


Question: ['4421', '7931', '1285', 'M', '7241', '7763', 'l', '6001', 'i', 'L', '7793', '2013', '8763', 'U', '5249', 'O', '473', '9811']

Answer:
68744