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: ['7763', '6003', 'V']

Answer: 13766


Question: ['K', '5791', '3415', '593', '1047', 'p', 'F', 'U', 'z', 'b', '497', '8635', '8639', 'A', '3025', 'r', '3241', 'r']

Answer:
34883