TASK DEFINITION: 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.
PROBLEM: ['901', '1939', '7637', '8863', 'X', '5003', '8791', '4757', 'E', '1525', 'y', '9735']

SOLUTION: 49151

PROBLEM: ['8871', '1297', 'W', 'f', 'Y', '8731', '113', '6707', '379', '9631', 'X', 'C', 'q']

SOLUTION: 35729

PROBLEM: ['779', '639', 'D']

SOLUTION:
1418