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: ['R', 'J', 'z', 'o', '1121', '7247', '8987', 'u']

SOLUTION: 17355

PROBLEM: ['D', '5207', 'E', '119', 'g', '2991', 'G', 'g', 'u']

SOLUTION: 8317

PROBLEM: ['7539', '4603', '7737', 'a', '1279', '8281', '5901', 'v', 'q', 'd', 'k', '4199', 'K', 'Z', '9247', '8151', '2917', 'R', '2643', 'd']

SOLUTION:
62497