instruction:
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.
question:
['3121', 'j']
answer:
3121


question:
['P', '237', 'X', '8893', '7931', 'F', '8359', 'S', '6931', '6953', 'r']
answer:
39304


question:
['j', 'f', '3831', 'B', 'D']
answer:

3831