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: ['e', '6633', '131', '7459', '3733']

SOLUTION: 17956

PROBLEM: ['4949', '2459', 'n', 'f', 'n', 'v', '8421', '1519', '4859', 'c', '9923', '2829', 'K', '4937', 'W', 'R']

SOLUTION: 39896

PROBLEM: ['393', 'q', 'a']

SOLUTION:
393