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.

['3693', '103', '9625', 'I', '1937', 'S', '6511', '339', 'r', '823', '2111', 'Y', 'B', 'X', '2031', '499', '1967', 'I', 'C']
29639