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

['1671', 'H', '9271']
10942

['8509', 'x', 'q', 'h', '7273', 'k', 's', 't', 'x', 'B', 'E', 'j', '9963', 'O', 'L']

25745