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: ['6867', 'x', '8481', '5091', '979', 'a', 'S', 'i', 'd', '1591']

SOLUTION: 23009

PROBLEM: ['8871', '1297', 'W', 'f', 'Y', '8731', '113', '6707', '379', '9631', 'X', 'C', 'q']

SOLUTION: 35729

PROBLEM: ['P', 'M', '7367', '7069', '3505', '1863', '6307', '7005', 'F', 'D', '3855', '7957']

SOLUTION:
44928