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: ['k', 'a']
Example Output: 0

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: ['699', 'S', 'D', '4791', '1221', 'a', '4977', '4177', 'V', 'I', 'x', '6613', 't', 'f', 'R', '1867', '5425', 'E', '1929', '9351']
Example Output:
41050