



'''simple docstring'''


from math import factorial






def  UpperCAmelCase_       (		lowercase__ = 2_0       )     ->   List[Any]:


     '''simple docstring'''







     a_       		=2 * n  # middle entry of odd rows starting at row 3 is the solution for n = 1,
     # 2, 3,...
     a_       		=n // 2

     return int(factorial(lowercase__       ) / (factorial(lowercase__       ) * factorial(n - k       ))       )


if __name__ == "__main__":
  import sys

  if len(sys.argv) == 1:
    print(solution(20))
  else:
    try:
      lowercase							       =			int(sys.argv[1])
      print(solution(n))
    except ValueError:
      print('''Invalid entry - please enter a number.''')







'''simple docstring'''


from collections.abc import Generator






def  UpperCAmelCase_       (		):


     '''simple docstring'''







     a_		,						a_       		=0, 1
     while True:
          a_		,						a_       		=b, a + b
          yield b






def  UpperCAmelCase_       (		lowercase__ = 1_0_0_0       ):


     '''simple docstring'''







     a_       		=1
     a_       		=fibonacci_generator()
     while len(str(next(lowercase__       )       )       ) < n:
          answer += 1
     return answer + 1


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


