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: ['r', 'z', 'u', 'D', '3449', 'E', 'f', 'w', '1627', '4093', '955', 'i', 's', 'R', 'b', '9773', '2169', 'M', '9305', '4775']

SOLUTION: 36146

PROBLEM: ['4177', 'd', 'b', 'm', 'f', 'R', '797', '7905', '4355', '7515', '9801', 'F', 'R', '9125', '8445', 'k', 'K', 'K']

SOLUTION: 52120

PROBLEM: ['1625', '8861', 'q', '6451', '871', 'O', 'Y', 'i']

SOLUTION:
17808