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.

Example Input: ['r', 'B', '8791', '3165', 'n', 'm']
Example Output: 11956

Example Input: ['e', '6633', '131', '7459', '3733']
Example Output: 17956

Example Input: ['F', 'x', '6751', '9869', 'Z', 'x', '3945', 'C', '1355', '9329', 'l', '9181']
Example Output:
40430