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: ['u', 'e', 'P', 'D', '255', '2573', 'E', 'P', 's', '3725', '3391', 'I', '5323', '885']

SOLUTION: 16152

PROBLEM: ['M', '5201', '2787', 'z', '9465', 'X', 'X', '4017', '8305', 'y', '6897', 'y', '6045', '9863', 's', 'd', '3611', 'l', 'd']

SOLUTION: 56191

PROBLEM: ['7929', 'X', '3217', 'L', 'k', '7917', '7529', '2559', '53', 'k', 'h', 'v', '5005']

SOLUTION:
34209