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: ['2787', '6085', '6989']

SOLUTION: 15861

PROBLEM: ['U', '5885', 'u', 'Y', 's', 'w', 'j', '9629', '9505', 'U']

SOLUTION: 25019

PROBLEM: ['G', 'o', 's', 'P', '655', '6375', '6401', '1899', 'R', 'C', '9477']

SOLUTION:
24807