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: ['339', 'h', 'd', '7449', 'e', 'u', '5055', '7029', '9009', 'G', 'U', '3', '441', '3273', 'K', '3827', '7069', 'x']
Example Output: 43494

Example Input: ['3907', 'x', 'W', 'S', '7163', '5913', 'X', 'V', 'R', 'P', '5639', '5203', 'C']
Example Output:
27825