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]: ['3557', '3345', '307', '9791', '1897', 'O']
[EX A]: 18897

[EX Q]: ['m', '3481']
[EX A]: 3481

[EX Q]: ['v', 'Z', 'p', '415', '2055', 'L', 'K', '8055', 'X', 'm', '5357', 'E', '1255']
[EX A]:
17137