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: ['9905', 'm', 'Q', 'S', 'T', '7821', '1773', '9515', '3963', '2931', '7023', '8677', '1739', 'O', '909', '9153', '8319', 'k', '2851']

SOLUTION: 74579

PROBLEM: ['z', 'T', 'Y', 's', 'j', '585', '7833', '2601', '8057', 'S', '7037', '5799', '4477', '5377', '6301', 'P', 'm', '9431', 'f']

SOLUTION: 57498

PROBLEM: ['T', 'g', 'w', '9763', '269', 'C', 's', '8263', 'I', 'w', 't', 'F', '7577']

SOLUTION:
25872