from abc import ABC, abstractmethod
from argparse import ArgumentParser


class 			UpperCAmelCase__    (		snake_case					):



  """simple docstring"""






  @staticmethod
  @abstractmethod
  def 	_UpperCAmelCase				(				__lowerCAmelCase:			ArgumentParser   ) -> Tuple:




    '''simple docstring'''




    raise NotImplementedError()






  @abstractmethod
  def 	_UpperCAmelCase				(				self:			List[str]   ) -> List[Any]:




    '''simple docstring'''




    raise NotImplementedError()




def       __lowerCAmelCase      (						A_   : str					)    ->  bool:
  if not all(x.isalpha() for x in string					):
    raise ValueError("String must only contain alphabetic characters."					)

  __UpperCAmelCase						    =       sorted(string.lower()					)
  return len(A_					) == len(set(A_					)					)


if __name__ == "__main__":
       a_							=      input("""Enter a string """).strip()

       a_							=      is_isogram(input_str)
       print(F"{input_str} is {'an' if isogram else 'not an'} isogram.")



