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.

['D', 'R', 'Y', '4929', 'P', '7929']
12858

['D', '7807', '9395', 'T', 'c', '5139', '2827', 't', 'T', 'm', '3717', 'U', '3225', '7419', '2481', 'p', 'C', '5277']
47287

['2513', '251', 'x', 'K', 't', 'J']

2764