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: ['1319', '6105', '1119', 'c', 'p', '7617', '5113', 'a', '5115', '6731', '6693']
Example Output: 39812

Example Input: ['p', '4689']
Example Output: 4689

Example Input: ['r', '3589', '8407', 'Z', 'A', '1753', '4395', '2567']
Example Output:
20711