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.
['w', '2209', 'd', 'h', '3055', 'f', 'r', '103', '5209', 't', '9311', 'U', '8067', '3319', '285', 'B', '3055', 'H', '2183']