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.
One example: ['238', 'h', '92', 'U', '2799']
Solution is here: 3129
Explanation: Here, the numbers in the input list are '238', '92' and '2799', hence their sum (238+92+2799) is 3129.

Now, solve this: ['6019', '1467', '3415', '7785']
Solution:
18686