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: ['1073', 'i', 'o', 'j', 'O', 'g', 'X', '3261', '5105', '4831', 'J']

SOLUTION: 14270

PROBLEM: ['o', 'O', 'H', '7619', '6435', 'X', 'g', '1663']

SOLUTION: 15717

PROBLEM: ['s', 'D', 'N', '8267', 'o', 'v', 'R', 'k']

SOLUTION:
8267