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: ['7709', 'y', 'k', '8137', '5337', '6419', '5449', 'g', 'H', 'e', '311', '9315', 'Z', 'Z']
Output:

Show your work and conclude with the exact phrasing "Therefore, the final answer is [answer]." where [answer] is just the final number or expression that solves the problem.
user
42677