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.

Q: ['2787', 'z', '9351', '3339']

A: 15477
****
Q: ['a', 'f', '2185', 'N', '6381', '6429', '7499', 'd', '757', 'k', 'k', 'b', 'N', '2697', 'A', '8037']

A: 33985
****
Q: ['p', '4689']

A:
4689
****