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: ['d', '5571', '6455', '4287', 'I', 'U', 'M', '8303', '8893']

SOLUTION: 33509

PROBLEM: ['7669', '3367', 'A', 'Z', '6173', '4391', 'f', 'S', '9657', '2631']

SOLUTION: 33888

PROBLEM: ['H', 'e', '2209', '3461', 'a', '2391', '8231']

SOLUTION:
16292