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: ['S', '1249', '6233', 'I', '6733', 'r', 'A', 'E', 'h', 'x', 'p', 'c', '515', '1029', '1593', '1035']
Example Output: 18387

Example Input: ['2895', '8095', 'y', '1927', '4827']
Example Output: 17744

Example Input: ['1361', 'n', '7359']
Example Output:
8720