Detailed Instructions: 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: ['8879', 'Y', '6143', 'm', '463', 'G', '6891', 'v', '581', 's', 'n', 'F', 'z', 'D', 'S', '1489', '289']
A:
24735