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: ['l', 'B', 'Y', '7543', '5091', '1917']

SOLUTION: 14551

PROBLEM: ['K', 'p', '97', 'R', '2999', 'u', '7307', '6033', '6431', 'm', 'T']

SOLUTION: 22867

PROBLEM: ['4317', '6575', '2971', 'F', '4445', '1955', '1543', '1783']

SOLUTION:
23589