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.

['W', 'c', '7971', 'J', 'o']
7971

['7215', 'd', 'q', 'k', '9301', 'P', 'x', 'C', 'g', 'e', 'o', '2769', '6993', '9769', 'v', '9007', '4131', '8627', 'q']
57812

['5343', 'Z', 'U', '4769', 'E', 's', '5371', 'b', 'X', '2549', 'l', '3257', 'U']

21289