




'''simple docstring'''




from math import asin, atan, cos, radians, sin, sqrt, tan

UpperCAmelCase_				 =					6_3_7_8_1_3_7.0
UpperCAmelCase_				 =					6_3_5_6_7_5_2.3_1_4_2_4_5
UpperCAmelCase_				 =					6_3_7_8_1_3_7

def       _UpperCamelCase					( SCREAMING_SNAKE_CASE__	:					float				,  SCREAMING_SNAKE_CASE__	:					float				,  SCREAMING_SNAKE_CASE__	:					float				,  SCREAMING_SNAKE_CASE__	:					float				):
 '''simple docstring'''





 UpperCAmelCase__								=			(AXIS_A - AXIS_B) / AXIS_A
 UpperCAmelCase__								=			atan((1 - flattening) * tan(radians(__lowerCamelCase				)				)				)
 UpperCAmelCase__								=			atan((1 - flattening) * tan(radians(__lowerCamelCase				)				)				)
 UpperCAmelCase__								=			radians(__lowerCamelCase				)
 UpperCAmelCase__								=			radians(__lowerCamelCase				)
 # Equation
 UpperCAmelCase__								=			sin((phi_a - phi_a) / 2				)
 UpperCAmelCase__								=			sin((lambda_a - lambda_a) / 2				)
 # Square both values
 sin_sq_phi *= sin_sq_phi
 sin_sq_lambda *= sin_sq_lambda
 UpperCAmelCase__								=			sqrt(sin_sq_phi + (cos(__lowerCamelCase				) * cos(__lowerCamelCase				) * sin_sq_lambda)				)
 return 2 * RADIUS * asin(__lowerCamelCase				)


if __name__ == "__main__":
    import doctest

    doctest.testmod()







'''simple docstring'''


def 							UpperCAmelCase_  (						__lowerCamelCase					:					int = 10_00 ):
   lowercase_			,							lowercase_			:str    			= 1, 1
   lowercase_			:Any    			= 2
   while True:
      lowercase_			:str    			= 0
      lowercase_			:Tuple    			= fa + fa
      lowercase_			,							lowercase_			:Tuple    			= fa, f
      index += 1
      for _ in str(__lowerCamelCase ):
         i += 1
      if i == n:
         break
   return index


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


