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

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

Example Input: ['d', '2477', '8129', 'O', '3173']
Example Output:
13779