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: ['6669', 'n', 't', 'N', 'x', '8153', 'W', 'v', 'B', '3181', 'y', 'e', '3491']

SOLUTION: 21494

PROBLEM: ['T', 'n', '8513', '5565', '6343', '1403', '975', '6959', '8049', '1601', 'j', 'Q', 'O', '7889', 'r', 'D', '1903', '6607']

SOLUTION: 55807

PROBLEM: ['4363', 'W', '2477', 'o', 'C', 'G', '9893', '2037', 'F', 'J', '6385', '7269', '343', '1163', 'Q', 'A', 'O', '4747']

SOLUTION:
38677