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.

['R', 'C', 'S', 'x', '1529', 'r']
1529

['5233', 'i', 'Z', 'v', '4531', 'j', '61', '1725', '5915', '1677', 'F', 'K', 'M', 'Z']
19142

['w', '4181', 'g', 'j', '1823', 'q', 'i', '709']

6713