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.

[EX Q]: ['6867', 'x', '8481', '5091', '979', 'a', 'S', 'i', 'd', '1591']
[EX A]: 23009

[EX Q]: ['7669', '3367', 'A', 'Z', '6173', '4391', 'f', 'S', '9657', '2631']
[EX A]: 33888

[EX Q]: ['619', '965', 'M']
[EX A]:
1584