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.
['4199', 'K', '8429', '3909', 'f', '8689', '9669', '915', '2889', '1105', 'F', 'C', 'q', '1103', '6635', '9679', '9001', '6197']