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: ['Q', '9787', '7533', '9489', 'C', '1753', '5121', '1405', '9267', '4815', 's', '5887']
Example Output: 55057

Example Input: ['3451', '2325', '2511', 'i', '6159', '2291', 'e', 'l', 'P', '1177', 'o', 'T']
Example Output: 17914

Example Input: ['B', 'c', 'N', 'Z', 't', 'm', 'w', 'R', '9157', 'S', 'h', '4411', '7335']
Example Output:
20903