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: ['2087', '8171', 'c', 'd', 'a', '5621', 'n']

SOLUTION: 15879

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

SOLUTION: 33888

PROBLEM: ['D', 'Q', 't', '1151', '7243', '1391', '2161']

SOLUTION:
11946