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]: ['R', 'J', 'z', 'o', '1121', '7247', '8987', 'u']
[A]: 17355


[Q]: ['2787', 'z', '9351', '3339']
[A]: 15477


[Q]: ['5517', '9053', '7851', '5003', '1099', 'b', 'M', '7685', 'T']
[A]:
36208