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.
['7641', '7873', '1573', '6829', '3763', '5063', '5315', 'p', '261', 'x', 'd', 'J', '2611', 'M', 'B', '2283', '9235', '8733', '2625']