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: ['1709', 'S', 'w', '7725', 'Z', '7755', '8081', '897', 'N', '4449', 'F', 'F', 'M', 'y', 'B', 'h', 's', 'l', 's', '415']

SOLUTION: 31031

PROBLEM: ['k', '1489', 'x', '6543', 'I', 'l', 'D', '6299', '1473', 'a', '7661', 'z', 'E', 'Z', 'U', '3671', '2873', 'e', 'p']

SOLUTION: 30009

PROBLEM: ['3699', '5807', 'N', 'n', 'P', '4111', 'y', '3311', 'N', '2145', 'v', '1485', '8317', '5271', 'g', 'S']

SOLUTION:
34146