new_contents: # -*- coding:utf-8 -*-
  class Solution:
      # @param n, an integer
      # @return an integer
      def climbStairs(self, n):
          a = b = 1
          n = n - 1
          while n > 0:
              tmp = a
              a = a + b
              b = tmp
              n -= 1
          return a
  
subject: add leetcode Climbing Stairs