# -*- coding:utf-8 -*-
class Solution:
    def Sum_Solution(self, n):
        # write code here
        return sum(list(range(1,n+1)))

class Solution:
    def Sum_Solution(self, n):
        # write code here
        result=n
        temp=n>0 and self.Sum_Solution(n-1)
        result+=temp
        return result