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: ['I', '1941', '2423', '3381', 'J', '6589', 'h', 'D']
Example Output: 14334

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

Example Input: ['7215', '9379', 'R', 'o', '7223', '8221', '6443', 'U', 'R', 'T', '8253', '499', 'g', '1201', '1839', '6805']
Example Output:
57078