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', 'S', 'S', 'U', 'w', '7691', '7529', 'B', '3861', '4557', 'd', '569', '1547']

SOLUTION: 25754

PROBLEM: ['R', 'I', 'f', 'K', 'p', '8579', 'e', '1223', 'I', 'K', '8311', '2147', '4241', 'z', '6671', 'r']

SOLUTION: 31172

PROBLEM: ['o', '6149', 'p']

SOLUTION:
6149