input: Write a Python function that determines if a given hexadecimal number is even or odd.
  assert even_or_odd("AB3454D") == "Odd"
  assert even_or_odd("ABC") == "Even"
  assert even_or_odd("AAD") == "Odd"
output: 
  def even_or_odd(hex_num):
      return "Even" if int(hex_num[-1], 16) % 2 == 0 else "Odd"
  