


def        _UpperCamelCase							(      lowercase__    ,       lowercase__      ):
						if len(lowercase__      ) != len(lowercase__      ):
												raise ValueError('''String lengths must match!'''      )

						__SCREAMING_SNAKE_CASE						:     List[Any]					=		0

						for chara, chara in zip(lowercase__    ,       lowercase__      ):
												if chara != chara:
																		count += 1

						return count


if __name__ == "__main__":
						import doctest

						doctest.testmod()








"""simple docstring"""



def 						lowercase    (				__snake_case				: int = 1_0_0_0	):
		lowercase_       ,					lowercase_ : str							       =   1, 1
		lowercase_ : List[str]							       =   2
		while True:
				lowercase_ : Tuple							       =   0
				lowercase_ : List[Any]							       =   fa + fa
				lowercase_       ,					lowercase_ : Optional[int]							       =   fa, f
				index += 1
				for _ in str(__snake_case	):
						i += 1
				if i == n:
						break
		return index


if __name__ == "__main__":
						print(solution(int(str(input()).strip())))



