





def      A__				(       SCREAMING_SNAKE_CASE__   ,   SCREAMING_SNAKE_CASE__   ,   SCREAMING_SNAKE_CASE__)  ->       float:
  if common_ratio == 1:
    # Formula for sum if common ratio is 1
    return num_of_terms * first_term

  # Formula for finding sum of n terms of a GeometricProgression
  return (first_term / (1 - common_ratio)) * (1 - common_ratio**num_of_terms)














'''simple docstring'''







def 					SCREAMING_SNAKE_CASE_			(UpperCamelCase							,     UpperCamelCase = 13 ) ->			str:
							lowerCamelCase__   :      Dict			    =			""""""
							for c in s:
														if "A" <= c <= "Z":
																					out += chr(ord("""A""" ) + (ord(UpperCamelCase ) - ord("""A""" ) + n) % 26 )
														elif "a" <= c <= "z":
																					out += chr(ord("""a""" ) + (ord(UpperCamelCase ) - ord("""a""" ) + n) % 26 )
														else:
																					out += c
							return out





def 					SCREAMING_SNAKE_CASE_			() ->			None:
							lowerCamelCase__   :      Dict			    =			input("""Enter message: """ )

							lowerCamelCase__   :      str			    =			dencrypt(UpperCamelCase							,     13 )
							print("""Encryption:"""							,     UpperCamelCase )

							lowerCamelCase__   :      List[str]			    =			dencrypt(UpperCamelCase							,     13 )
							print("""Decryption: """							,     UpperCamelCase )


if __name__ == "__main__":
			import doctest

			doctest.testmod()
			main()

