def DFS(numbers, total, target, answer):
if len(numbers)==0:
if total==target: answer.append(0)
else:
DFS(numbers[1:], total-numbers[0], target, answer)
DFS(numbers[1:], total+numbers[0], target, answer)
def solution(numbers, target):
answer = []
DFS(numbers, 0, target, answer)
return len(answer)