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

Example Input: ['n', 'W', '565', '6625', '903', 'o', '7995', '8339', '5251', 'e', 'a', '1081', '5813', 'o']
Example Output: 36572

Example Input: ['6739', '5427', 'k', 'd', '867', '9191', '2965']
Example Output:
25189