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: ['M', 'H', 'l', 'Y', '3811', '1953', '5869', 'U']

SOLUTION: 11633

PROBLEM: ['A', '771', 'Q', 'b', '9929', '4991', 'q', '9863', '4363', '5721', 'C', '991', 'j', 'r', 'Q', 'B', 'K']

SOLUTION: 36629

PROBLEM: ['6799', 'b', 'H', 'x', 'R', '6045', 'm', '7965']

SOLUTION:
20809