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: ['2787', 'z', '9351', '3339']
Example Output: 15477

Example Input: ['i', 'o', '1321', 'I', 'W', 'e', '1201', 'I', 'e', 'F', '9841', 'm', '9827', 'q', 'f', 'X', '8261']
Example Output: 30451

Example Input: ['X', '6561', 'Q', 'k', 'C', '8971', 'B', '3161']
Example Output:
18693