





_UpperCAmelCase				:       Optional[int]	   =				"ABCDEFGHIJKLMNOPQRSTUVWXYZ"


def        SCREAMING_SNAKE_CASE      (       )			->     List[Any]:
    lowerCamelCase__    :      Optional[Any]					 =		input('Enter message: ' )
    lowerCamelCase__    :      List[Any]					 =		input('Enter key [alphanumeric]: ' )
    lowerCamelCase__    :      Any					 =		input('Encrypt/Decrypt [e/d]: ' )

    if mode.lower().startswith('e' ):
        lowerCamelCase__    :      str					 =		'encrypt'
        lowerCamelCase__    :      Union[str, Any]					 =		encrypt_message(_lowerCamelCase						,	_lowerCamelCase )
    elif mode.lower().startswith('d' ):
        lowerCamelCase__    :      int					 =		'decrypt'
        lowerCamelCase__    :      str					 =		decrypt_message(_lowerCamelCase						,	_lowerCamelCase )

    print(F"""\n{mode.title()}ed message:""" )
    print(_lowerCamelCase )


def        SCREAMING_SNAKE_CASE      (       _UpperCAmelCase						,	_UpperCAmelCase )			->     Union[str, Any]:
    return translate_message(_lowerCamelCase						,	_lowerCamelCase						,	'encrypt' )


def        SCREAMING_SNAKE_CASE      (       _UpperCAmelCase						,	_UpperCAmelCase )			->     int:
    return translate_message(_lowerCamelCase						,	_lowerCamelCase						,	'decrypt' )


def        SCREAMING_SNAKE_CASE      (       _UpperCAmelCase						,	_UpperCAmelCase						,	_UpperCAmelCase )			->     List[Any]:
    lowerCamelCase__    :      List[str]					 =		[]
    lowerCamelCase__    :      Dict					 =		0
    lowerCamelCase__    :      Optional[Any]					 =		key.upper()

    for symbol in message:
        lowerCamelCase__    :      Dict					 =		LETTERS.find(symbol.upper() )
        if num != -1:
            if mode == "encrypt":
                num += LETTERS.find(key[key_index] )
            elif mode == "decrypt":
                num -= LETTERS.find(key[key_index] )

            num %= len(_lowerCamelCase )

            if symbol.isupper():
                translated.append(LETTERS[num] )
            elif symbol.islower():
                translated.append(LETTERS[num].lower() )

            key_index += 1
            if key_index == len(_lowerCamelCase ):
                lowerCamelCase__    :      List[str]					 =		0
        else:
            translated.append(_lowerCamelCase )
    return "".join(_lowerCamelCase )


if __name__ == "__main__":
    main()












'''simple docstring'''

from __future__ import annotations






class    UpperCAmelCase	:
 def __init__(				self      :Optional[int]						,       lowercase_      :int							)->							None:
     A__				=			order

     # a_{0} ... a_{k}
     A__				=			[1.0] + [0.0] * order
     # b_{0} ... b_{k}
     A__				=			[1.0] + [0.0] * order

     # x[n-1] ... x[n-k]
     A__				=			[0.0] * self.order
     # y[n-1] ... y[n-k]
     A__				=			[0.0] * self.order
 def      UpperCAmelCase_							(				self      :List[str]						,       lowercase_      :list[float]						,       lowercase_      :list[float]							)->							None:
     if len(lowercase_							) < self.order:
         A__				=			[1.0, *a_coeffs]

     if len(lowercase_							) != self.order + 1:
         A__				=			(
             F"Expected a_coeffs to have {self.order + 1} elements "
             F"for {self.order}-order filter, got {len(lowercase_							)}"
         )
         raise ValueError(lowercase_							)

     if len(lowercase_							) != self.order + 1:
         A__				=			(
             F"Expected b_coeffs to have {self.order + 1} elements "
             F"for {self.order}-order filter, got {len(lowercase_							)}"
         )
         raise ValueError(lowercase_							)

     A__				=			a_coeffs
     A__				=			b_coeffs



 def      UpperCAmelCase_							(				self      :Optional[int]						,       lowercase_      :float							)->							float:
     A__				=			0.0

     # Start at index 1 and do index 0 at the end.
     for i in range(1						,       self.order + 1							):
         result += (
             self.b_coeffs[i] * self.input_history[i - 1]
             - self.a_coeffs[i] * self.output_history[i - 1]
         )

     A__				=			(result + self.b_coeffs[0] * sample) / self.a_coeffs[0]

     A__				=			self.input_history[:-1]
     A__				=			self.output_history[:-1]

     A__				=			sample
     A__				=			result

     return result



