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: ['3705', '9217', 'C', '4609']
Example Output: 17531

Example Input: ['d', '7305', '8903', 'b', '7687', '6393', '6939']
Example Output: 37227

Example Input: ['7583', 'x', 'B', 'i', 'V', 'l', '867', '7699', '5385', '6447', 'e', 'f', '4473', '3993']
Example Output:
36447