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.

['D', 'm', 'P', '2433', '6731']
9164

['6321', 'M', 'd', '3673']
9994

['L', '2347', '129', '8935', '4885', 'R', '3375', 'J', '827', 'I', 'x', '3871', '5069']

29438