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: ['a', 'm', '3205', '1869', '1117', 'K', '5785']
Example Output: 11976

Example Input: ['d', '4553']
Example Output: 4553

Example Input: ['R', 'm']
Example Output:
0