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: ['5199', 'h', 'T', 'T', 'l', '1661', 'p']

SOLUTION: 6860

PROBLEM: ['4425', 'x', '1959', 'C', 'c', 'D', 'M', '8317', 'q', 'x', '4277', 'N', 'z', 'I', '1921', 'o', 't']

SOLUTION: 20899

PROBLEM: ['5439', 'm', '7269', 'q', '7305', 'n']

SOLUTION:
20013