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: ['J', '5149', 'H', 'L', 'm', 'h', '3863', 'n', 'z']

SOLUTION: 9012

PROBLEM: ['q', '6631', 'b', '4207', '7523', '9853', '9203', 'P', '5029', 'b', '2319', '4717', '2485']

SOLUTION: 51967

PROBLEM: ['R', 'k', '7843', 'S', 'e']

SOLUTION:
7843