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: ['d', '5571', '6455', '4287', 'I', 'U', 'M', '8303', '8893']
Example Output: 33509

Example Input: ['v', 'a', 'O', 'S', 'r', 'T', 'r', 'K', 'K', '7781', '1749']
Example Output: 9530

Example Input: ['y', 'm', '5541', '747', '4265', '9603', 'q', '9721', '9881', 'L', '6427', '8441', '6301', '617', 'K', 'U', 'Y', '319', '9035']
Example Output:
70898