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: ['A', '9979', '8723', '1131', 'i', 'p', 'M']

SOLUTION: 19833

PROBLEM: ['d', 'b', 'W', '3201', 'C', 'o', '5187', '9723', '8177', 'F', '6703', 'U', '1393', '1035', '3507', '5993', '3857', 'r', 'C', 'j']

SOLUTION: 48776

PROBLEM: ['U', 'd', '3499', 'S', 'c', 'P', 'v', '5861', '625']

SOLUTION:
9985