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.

['6787', 'W', 'I', '4929', 'j', 'I', '3487', 'F', '3927', 'Q', 's', 'X', '9939', 'n']
29069

['T', 'n', '8513', '5565', '6343', '1403', '975', '6959', '8049', '1601', 'j', 'Q', 'O', '7889', 'r', 'D', '1903', '6607']
55807

['N', '8241', 'b']

8241