code: def _preprocess(inp):
          inp = re.sub(r'(\b)a(\b)', r'\g<1>one\g<2>', inp)
          inp = re.sub(r'to the (.*) power', r'to \g<1>', inp)
          inp = re.sub(r'to the (.*?)(\b)', r'to \g<1>\g<2>', inp)
          inp = re.sub(r'log of', r'log', inp)
          inp = re.sub(r'(square )?root( of)?', r'sqrt', inp)
          inp = re.sub(r'squared', r'to two', inp)
          inp = re.sub(r'cubed', r'to three', inp)
          inp = re.sub(r'divided?( by)?', r'divide', inp)
          inp = re.sub(r'(\b)over(\b)', r'\g<1>divide\g<2>', inp)
          inp = re.sub(r'(\b)EE(\b)', r'\g<1>e\g<2>', inp)
          inp = re.sub(r'(\b)E(\b)', r'\g<1>e\g<2>', inp)
          inp = re.sub(r'(\b)pie(\b)', r'\g<1>pi\g<2>', inp)
          inp = re.sub(r'(\b)PI(\b)', r'\g<1>pi\g<2>', inp)
          def findImplicitMultiplications(inp):
              def findConstantMultiplications(inp):
                  split = inp.split(' ')
                  revision = ""
                  converter = NumberService()
                  for i, w in enumerate(split):
                      if i > 0 and w in MathService.__constants__:
                          if converter.isValid(split[i - 1]):
                              revision += " times"
                      if not revision:
                          revision = w
                      else:
                          revision += " " + w
                  return revision
              def findUnaryMultiplications(inp):
                  split = inp.split(' ')
                  revision = ""
                  for i, w in enumerate(split):
                      if i > 0 and w in MathService.__unaryOperators__:
                          last_op = split[i - 1]
                          binary = last_op in MathService.__binaryOperators__
                          unary = last_op in MathService.__unaryOperators__
                          if last_op and not (binary or unary):
                              revision += " times"
                      if not revision:
                          revision = w
                      else:
                          revision += " " + w
                  return revision
              return findUnaryMultiplications(findConstantMultiplications(inp))
          return findImplicitMultiplications(inp)