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: ['D', 'K', 'n', 'd', 'i', 'U']

A: 0
****
Q: ['3145', 'C', '7725', 'k', 'z']

A: 10870
****
Q: ['t', 'G', '4989']

A:
4989
****