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.
--------
Question: ['8739', 'K']

Answer: 8739


Question: ['n', 'm', 'Y', 'v']

Answer: 0


Question: ['1389', 'S', '5423', 's', 'T', 'D', '8125', '6611', '4173', '273', 'H', '8555', '7969', 'k', '5357', 'i']

Answer:
47875