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: ['J', 'm', '1255', 'S']

SOLUTION: 1255

PROBLEM: ['P', '6299', '9655', 'l', '6317', '2139', '3347', 'l', '3095', '7363', '3115', '7529', 'R']

SOLUTION: 48859

PROBLEM: ['745', 'p', 'h', 'r', 'B', '6023', '213', 'U', 'U', '9779', 'X', 'e', 'B', '5025', 'x', '6243', 'r', 'P', '3335']

SOLUTION:
31363