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]: ['3145', 'C', '7725', 'k', 'z']
[EX A]: 10870

[EX Q]: ['S', 'D', '3101', '4967', '8197', '5025', '4257', 'S', 'X', '7641', 'n', '6775', '4719', 'o', '2821', 'x', '5605', '2181']
[EX A]: 55289

[EX Q]: ['7169', '2409', 'x', '3497', 'X', '4545', 'i', '7999', 'l', '7807', 'n', 'p', '7831']
[EX A]:
41257