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.

Example Input: ['1391', '1719', '8547', 'x', 'a', 'j', '6395', 't', '3421', '6607', 'M', '1645', 'H', 'x', 't']
Example Output: 29725

Example Input: ['P', '237', 'X', '8893', '7931', 'F', '8359', 'S', '6931', '6953', 'r']
Example Output: 39304

Example Input: ['3741', 'W', 'R', 'N', 'e', 'F', 'G', '8867', 'R', 'J', '5561', '9727', '7863']
Example Output:
35759