




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

_A     =			6_378_137.0
_A     =			6_356_752.314_245
_A     =			6_378_137





def __UpperCamelCase			(       _A ,  _A ,  _A ,  _A  ):
						lowerCAmelCase_      			=  (AXIS_A - AXIS_B) / AXIS_A
						lowerCAmelCase_      			=  atan((1 - flattening) * tan(radians(_A  )  )  )
						lowerCAmelCase_      			=  atan((1 - flattening) * tan(radians(_A  )  )  )
						lowerCAmelCase_      			=  radians(_A  )
						lowerCAmelCase_      			=  radians(_A  )
						# Equation
						lowerCAmelCase_      			=  sin((phi_a - phi_a) / 2  )
						lowerCAmelCase_      			=  sin((lambda_a - lambda_a) / 2  )
						# Square both values
						sin_sq_phi *= sin_sq_phi
						sin_sq_lambda *= sin_sq_lambda
						lowerCAmelCase_      			=  sqrt(sin_sq_phi + (cos(_A  ) * cos(_A  ) * sin_sq_lambda)  )
						return 2 * RADIUS * asin(_A  )


if __name__ == "__main__":
						import doctest

						doctest.testmod()










def __UpperCamelCase			(       _A = 1000000  ):
						lowerCAmelCase_      			=  1
						lowerCAmelCase_      			=  1
						lowerCAmelCase_      			=  {1: 1}

						for inputa in range(2 ,  _A  ):
												lowerCAmelCase_      			=  0
												lowerCAmelCase_      			=  inputa

												while True:
																		if number in counters:
																								counter += counters[number]
																								break
																		if number % 2 == 0:
																								number //= 2
																								counter += 1
																		else:
																								lowerCAmelCase_      			=  (3 * number) + 1
																								counter += 1

												if inputa not in counters:
																		lowerCAmelCase_      			=  counter

												if counter > pre_counter:
																		lowerCAmelCase_      			=  inputa
																		lowerCAmelCase_      			=  counter
						return largest_number


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




