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: ['6669', 'n', 't', 'N', 'x', '8153', 'W', 'v', 'B', '3181', 'y', 'e', '3491']
Example Output: 21494

Example Input: ['Q', '8841', 'H', 'v', '2435', '8221', '807', 'P', '2247', 'M', '4609', '5657', 'k', '2807', 'j', '8451']
Example Output: 44075

Example Input: ['9671', '1803', '6709', 'H', 'M', 'H', 'N', 'h', 'l']
Example Output:
18183