Definition: 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.
Input: ['3763', '7847', 'i', 's', 'q', 'S', '2475', '3331', '609', 'L', '3335', '7829', '1073', '3411', '53', 'L', '6715']
Output:
40441