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: ['6669', 'n', 't', 'N', 'x', '8153', 'W', 'v', 'B', '3181', 'y', 'e', '3491']

Answer: 21494


Question: ['o', 'O', 'H', '7619', '6435', 'X', 'g', '1663']

Answer: 15717


Question: ['O', '1439', 'q', 'r', '9059', 'U', '8149']

Answer:
18647