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: ['l', '5369', 'z', 'U', 's', '2357', '3367', 't', '6539', 'K', 'a', 'Q', 'x', 'e', '6459', 'K', 'B', 'f', 'j']
Example Output: 24091

Example Input: ['t', 'v', 'B', 'Y']
Example Output: 0

Example Input: ['5687', 'I', 'q', 'n', 'e', '9909', '6825', 'j', '1513', '3175', 'q', 'K', '8805', '8095', '365', '7269', 't']
Example Output:
51643