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: ['5573', '6221', 'C', '8649', '6603', 'q', '9403']

SOLUTION: 36449

PROBLEM: ['4997', '5005', '6773', 'q', 'K', '8391', '7303', 'K', 'N', '5417', '8573', 'z', '8653', '8343', 'm', 'L', '1587', 'p', '5323']

SOLUTION: 70365

PROBLEM: ['z', 'S', '4947', 'h', '7809', '7389', '3839', '8551', 'Y', 'A', '71', 'W', '7941', '8155', '9731']

SOLUTION:
58433