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: ['s', 'M', 'U', '5383']

SOLUTION: 5383

PROBLEM: ['6849', 'I', 'p', 's', 'L', '4757', 'j', 'x', 'm', 'P', '5237', '1105', '9015', '9279', 'Q']

SOLUTION: 36242

PROBLEM: ['a', 'A', 'E', '7957', 'X', '785', '8693']

SOLUTION:
17435