text: # -*- coding: utf-8 -*-
  """
  Created on Fri Oct  5 02:31:49 2018
  
  @author: JinJheng
  """
  
  num=int(input("輸入一0~15之整數\n"))
  if num<10:
      print(num)
  elif num%10==0:
      print("A")
  elif num%10==1:
      print("B")
  elif num%10==2:
      print("C")
  elif num%10==3:
      print("D")
  elif num%10==4:
      print("E")
  elif num%10==5:
      print("F")
  else:
      print()