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]: ['R', 'C', 'S', 'x', '1529', 'r']
[EX A]: 1529

[EX Q]: ['J', 'm', '1255', 'S']
[EX A]:
1255