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: ['5215', 'c', '839', 'V']

Answer: 6054


Question: ['9989', 'B', 'E', '5181']

Answer: 15170


Question: ['1785', 'k', '747', '6861', '1957', 'N', '6219', 'L', 'S', '4101', '8609', 'n', 'z']

Answer:
30279