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: ['s', 't', 'W', '163', 'v']

SOLUTION: 163

PROBLEM: ['2011', '4965']

SOLUTION:
6976