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: ['N', 'V', 't', 'X', 't', 'M']

A: 0
****
Q: ['k', 'a']

A: 0
****
Q: ['4639', '1595', 'O', '999', 'E', '3771', '1157']

A:
12161
****