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: ['3433', '6955', 'Q', 'E', '3557', 'S', '2931', '9879', 'S', 'f', 'Q']

Answer: 26755


Question: ['R', 'k', '3355', 'Y', '6635', 'M', '4839', 'T', 'd', '495', 'g', 'E', 'g', 'F', 'S', '5377', 'g']

Answer: 20701


Question: ['4129', '4873', 'g', '7749', 'x']

Answer:
16751