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.

['4515', '3911', 'M', 'T', 'w', 'F']
8426

['3145', 'C', '7725', 'k', 'z']
10870

['6645', '9945', '717', '8029', 'X', '6247', 'U', '9849', 'U', 'Y', 's', 'S', 'n', '387']

41819