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: ['9869', '7701', 'H', 'o', 'v', '1431', 'O', 'L']
Example Output: 19001

Example Input: ['B', 'C', '8375', 'K', 'P', 'F', '6065', '5801', 'f', 'H', 'm', '4543', 'S', 'H', '6919', 'R', 's', 'j', '1997', 'V']
Example Output:
33700