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: ['2913', 'b', 'j', '7591', 'O', 's', '5589', '4995', '7503', 'U', 'S', 'C', '6797']

SOLUTION: 35388

PROBLEM: ['773', 'e', '4451', 'S', 'I', 'r', 'e', 'V', 'Q', 'g', 'J', 'L', '7655', 'O']

SOLUTION: 12879

PROBLEM: ['6867', 'x', '8481', '5091', '979', 'a', 'S', 'i', 'd', '1591']

SOLUTION:
23009