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:
['291', 'R', 'N', '983', '2879', 'C', '3797', '4837', '793', '5489', 'k', '535', 'L', '3605', 's', '3701', 'U', '4399', '2489', '4739']
answer:
38537


question:
['b', 's', 'v', '4757', '9063', 'I', '8397', '7975', 'Q']
answer:
30192


question:
['8795', '791', '4031', '9415', 'x', 'Y', '8009']
answer:

31041