new_contents: #!/usr/bin/env python3
  # -*- coding: utf-8 -*- 
  
  #   Copyright 2014 Fabian M.
  #
  #   Licensed under the Apache License, Version 2.0 (the "License");
  #   you may not use this file except in compliance with the License.
  #   You may obtain a copy of the License at
  #
  #       http://www.apache.org/licenses/LICENSE-2.0
  #
  #   Unless required by applicable law or agreed to in writing, software
  #   distributed under the License is distributed on an "AS IS" BASIS,
  #   WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
  #   See the License for the specific language governing permissions and
  #   limitations under the License.
  
  # Generate a christmas tree in ASCII.
  #
  # Keyword arguments:
  # z -- the height of the christmas tree minus the base (height = z + 1)
  # Returns a multiple line string containing the ASCII christmas tree.
  def tree(z):
  	# This is evil!
  	return "\n".join("".join(l) \
  		for l in map((lambda y: list(("*", "-")[x < y or x > 2*z-y-2] \
  		for x in range(0, 2*z-1))), reversed([z-1]+list(range(0, z)))))
  
  if __name__ == "__main__":
      	print(tree(int(input())))
  
subject: Add solution for problem 1a