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.
['Y', '6111', 'p', '2651', '4085', 'd', 'c', 'D', '453', 'R', '9163', 'S', 'y', 'P', '5753', '8429', '1247', 'Q', 'O']