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: ['5573', '6221', 'C', '8649', '6603', 'q', '9403']
Example Output: 36449

Example Input: ['V', 'h', '5549', 'K', 's', '8337', 'Y', '497', 'z', 'T', '4467', '6333', 'M', '1573', 'y', 'O', '5499', 's', 't', '6205']
Example Output: 38460

Example Input: ['15', '6997', 'I', '3907', '3607', 'O', 'h', 'k', '2203', '4021', 'N']
Example Output:
20750