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: ['901', 'X', 'W', 'D', 'm', 'M', '59', '4855', '6523', 'R', '9781', '8271', '4449', '2221', '8391']
Example Output: 45451

Example Input: ['B', '9189', '3691', '2869', '1525', 'd', 'H', 'P', '8613', 'b', 'r', '5289', 'V', '6433', '8733', 'K', '8105', '1041', 'U', 'L']
Example Output: 55488

Example Input: ['r', 'F', 'Z', '7939', 'c', 'v', '3353', 'H', '543', 't', '3951', '2007']
Example Output:
17793