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.

['P', '237', 'X', '8893', '7931', 'F', '8359', 'S', '6931', '6953', 'r']
39304

['U', '5607', 'Q', 'j', 'I', '3745', '3031']
12383

['S', 'F', 'Y', '7417', '1987', 'H']

9404