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

['Q', '1669']
1669

['613', 'j', '3413', 'o', 'B', 'w', 'h', '267', 'M', '247', 't', '9445', '141', '5011', '5691']

24828