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]: ['4949', '2459', 'n', 'f', 'n', 'v', '8421', '1519', '4859', 'c', '9923', '2829', 'K', '4937', 'W', 'R']
[EX A]: 39896

[EX Q]: ['X', '989', 'U', '9551', '6385', 'Y', '1433', 'J', '1833', '685', 'u']
[EX A]: 20876

[EX Q]: ['n', 'R', 'A', 'N', '2731', 'p']
[EX A]:
2731