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: ['7755', '8383', 'y', 'k', '4869', '2809']

Answer: 23816


Question: ['W', '4453', '5895', 'Z', 'A', '7663', '2749', 'f', 'H', '6917', '1215', 'M', '1775', '5397', 'l', '8197', '5209', '8229', 'U']

Answer: 57699


Question: ['3719', '6623', '2945', '5891', '635', 'Y', '8601', 'e', 'S', '2649', 'S', 'x', '4437']

Answer:
35500