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: ['P', '237', 'X', '8893', '7931', 'F', '8359', 'S', '6931', '6953', 'r']

SOLUTION: 39304

PROBLEM: ['1203', '6179', '9835']

SOLUTION: 17217

PROBLEM: ['t', 'u', '9979', '7223', 'X', 'h', 'b', '525', '6121', 'Z', 'n', '5323', '9577', '2589', '7687', 'v', '8569']

SOLUTION:
57593