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.

['4241', 'E', '1807', '2877', '5125', '7625', 'S', '401', '5081', 'u', 'R', 'F']
27157

['5715', 'r', 'R']
5715

['g', 'k', 'F', '723', 't', '1991', 'K', 'i', '4413', '9669', '3937', 'C', 'F']

20733