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', '6383', 'P', '8455', '3881', '5821', 'e', 'v', '1421', 'Q', '6377', '3157', '6407', 'q']
41902

['o', '7099', 'G', 'v', 'H', 'J', 'k', '1607', 'i', '9765', '2489', '8031']
28991

['3561', 'n']
3561