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.
['B', 'f', 'B', '5659', '5351', '587', '7319', '3447', '69', '8701', 'd', 'R', '3825', 'U', 'H', 'E', 'Y', 'c']