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.

[Q]: ['m', 'g', '7251', '5873', '59', '7345']
[A]: 20528


[Q]: ['8591', 'J', 'l', 'l', '7023', 'N', 'n']
[A]: 15614


[Q]: ['3615', 'y', '4793', 'P', 'a', 'R']
[A]:
8408