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.

Example Input: ['D', 'G', '9895', '143', '37', 'S', '1539', 'x', 'a', 'x', 'B', 'i', '9719', '839']
Example Output: 22172

Example Input: ['2775', '7405', 'F', 'D', '9025', '827', 'e', 'j', 's', 'e', 'Q', '1137', 'G']
Example Output: 21169

Example Input: ['y', 'b', '8981', '21']
Example Output:
9002