from __future__ import annotations

from collections.abc import Iterator
from typing import Any





class UpperCAmelCase						:


				'''simple docstring'''






				def __init__(						self		,     lowercase ):



						"""simple docstring"""





						A_		:    Any         =				data
						A_		:    Node | None         =				None





class UpperCAmelCase						:


				'''simple docstring'''






				def __init__(						self ):



						"""simple docstring"""





						A_		:    Optional[Any]         =				None
						A_		:    Dict         =				None
				def __iter__(						self ):



						"""simple docstring"""





						A_		:    str         =				self.head
						while self.head:
								yield node.data
								A_		:    Optional[int]         =				node.next
								if node == self.head:
										break
				def __len__(						self ):



						"""simple docstring"""





						return sum(1 for _ in self )
				def __repr__(						self ):



						"""simple docstring"""





						return "->".join(str(lowercase ) for item in iter(self ) )
				def   lowerCAmelCase_       (						self		,     lowercase ):



						"""simple docstring"""





						self.insert_nth(len(self )		,     lowercase )
				def   lowerCAmelCase_       (						self		,     lowercase ):



						"""simple docstring"""





						self.insert_nth(0		,     lowercase )
				def   lowerCAmelCase_       (						self		,     lowercase		,     lowercase ):



						"""simple docstring"""





						if index < 0 or index > len(self ):
								raise IndexError('list index out of range.' )
						A_		:    Union[str, Any]         =				Node(lowercase )
						if self.head is None:
								A_		:    List[str]         =				new_node  # first node points itself
								A_		:    List[Any]         =				new_node
						elif index == 0:  # insert at head
								A_		:    Union[str, Any]         =				self.head
								A_		:    Optional[int]         =				new_node
						else:
								A_		:    int         =				self.head
								for _ in range(index - 1 ):
										A_		:    Union[str, Any]         =				temp.next
								A_		:    str         =				temp.next
								A_		:    Optional[int]         =				new_node
								if index == len(self ) - 1:  # insert at tail
										A_		:    Union[str, Any]         =				new_node
				def   lowerCAmelCase_       (						self ):



						"""simple docstring"""





						return self.delete_nth(0 )
				def   lowerCAmelCase_       (						self ):



						"""simple docstring"""





						return self.delete_nth(len(self ) - 1 )
				def   lowerCAmelCase_       (						self		,     lowercase = 0 ):



						"""simple docstring"""





						if not 0 <= index < len(self ):
								raise IndexError('list index out of range.' )
						A_		:    int         =				self.head
						if self.head == self.tail:  # just one node
								A_		:    str         =				None
						elif index == 0:  # delete head node
								A_		:    str         =				self.tail.next.next
								A_		:    int         =				self.head.next
						else:
								A_		:    Union[str, Any]         =				self.head
								for _ in range(index - 1 ):
										A_		:    Dict         =				temp.next
								A_		:    List[str]         =				temp.next
								A_		:    Optional[Any]         =				temp.next.next
								if index == len(self ) - 1:  # delete at tail
										A_		:    Optional[int]         =				temp
						return delete_node.data







				def   lowerCAmelCase_       (						self ):



						"""simple docstring"""





						return len(self ) == 0




def     UpperCamelCase						(	):
		'''simple docstring'''




		A_		:    Dict         =				CircularLinkedList()
		assert len(__lowercase     ) == 0
		assert circular_linked_list.is_empty() is True
		assert str(__lowercase     ) == ""

		try:
				circular_linked_list.delete_front()
				raise AssertionError  # This should not happen
		except IndexError:
				assert True  # This should happen

		try:
				circular_linked_list.delete_tail()
				raise AssertionError  # This should not happen
		except IndexError:
				assert True  # This should happen

		try:
				circular_linked_list.delete_nth(-1     )
				raise AssertionError
		except IndexError:
				assert True

		try:
				circular_linked_list.delete_nth(0     )
				raise AssertionError
		except IndexError:
				assert True

		assert circular_linked_list.is_empty() is True
		for i in range(5     ):
				assert len(__lowercase     ) == i
				circular_linked_list.insert_nth(__lowercase						,i + 1     )
		assert str(__lowercase     ) == "->".join(str(__lowercase     ) for i in range(1						,6     )     )

		circular_linked_list.insert_tail(6     )
		assert str(__lowercase     ) == "->".join(str(__lowercase     ) for i in range(1						,7     )     )
		circular_linked_list.insert_head(0     )
		assert str(__lowercase     ) == "->".join(str(__lowercase     ) for i in range(0						,7     )     )

		assert circular_linked_list.delete_front() == 0
		assert circular_linked_list.delete_tail() == 6
		assert str(__lowercase     ) == "->".join(str(__lowercase     ) for i in range(1						,6     )     )
		assert circular_linked_list.delete_nth(2     ) == 3

		circular_linked_list.insert_nth(2						,3     )
		assert str(__lowercase     ) == "->".join(str(__lowercase     ) for i in range(1						,6     )     )

		assert circular_linked_list.is_empty() is False


if __name__ == "__main__":
	import doctest

	doctest.testmod()







_UpperCAmelCase            =		"""ABCDEFGHIJKLMNOPQRSTUVWXYZ"""




def     UpperCamelCase						(	):
		'''simple docstring'''




		A_		:    Tuple         =				input('Enter message: '     )
		A_		:    int         =				input('Enter key [alphanumeric]: '     )
		A_		:    Optional[Any]         =				input('Encrypt/Decrypt [e/d]: '     )

		if mode.lower().startswith('e'     ):
				A_		:    List[Any]         =				'encrypt'
				A_		:    int         =				encrypt_message(__lowercase						,__lowercase     )
		elif mode.lower().startswith('d'     ):
				A_		:    Optional[Any]         =				'decrypt'
				A_		:    Dict         =				decrypt_message(__lowercase						,__lowercase     )

		print(f'''\n{mode.title()}ed message:'''     )
		print(__lowercase     )




def     UpperCamelCase						(	__lowercase						:			str						,__lowercase						:			str     ):
		'''simple docstring'''




		return translate_message(__lowercase						,__lowercase						,'encrypt'     )




def     UpperCamelCase						(	__lowercase						:			str						,__lowercase						:			str     ):
		'''simple docstring'''




		return translate_message(__lowercase						,__lowercase						,'decrypt'     )




def     UpperCamelCase						(	__lowercase						:			str						,__lowercase						:			str						,__lowercase						:			str     ):
		'''simple docstring'''




		A_		:    Tuple         =				[]
		A_		:    str         =				0
		A_		:    Optional[int]         =				key.upper()

		for symbol in message:
				A_		:    Optional[Any]         =				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(__lowercase     )

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

						key_index += 1
						if key_index == len(__lowercase     ):
								A_		:    str         =				0
				else:
						translated.append(__lowercase     )
		return "".join(__lowercase     )


if __name__ == "__main__":
	main()






