input: Write a function that converts a given positive integer to its negative representation or vice versa using the bitwise NOT operator. Define two functions, one for converting positive to negative and another for converting negative to positive.
  assert convert_to_negative(5) == -5
  assert convert_to_positive(-5) == 5
  assert convert_to_negative(0) == 0
  assert convert_to_positive(0) == 0
output: def convert_to_negative(n):
      return ~n + 1
  
  def convert_to_positive(n):
      return ~n + 1