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.

['2915', '4443', 'Z', '3409', '1417', 'H', 'T', 'u', '3373', 'U', '115', 'R']
15672

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

['4665', 'Y', 's', 'R', 'S', '6743', 'G', 'W', 'h', '5053', 'n', 'L', 'M', 'p']

16461