



from __future__ import annotations

from math import pi, pow



def __lowerCAmelCase       (   SCREAMING_SNAKE_CASE_     ):
			if side_length < 0:
						raise ValueError("vol_cube() only accepts non-negative values"     )
			return pow(SCREAMING_SNAKE_CASE__  ,     3     )



def __lowerCAmelCase       (   SCREAMING_SNAKE_CASE_  ,     SCREAMING_SNAKE_CASE_     ):
			if height < 0 or radius < 0:
						raise ValueError("vol_spherical_cap() only accepts non-negative values"     )
			# Volume is 1/3 pi * height squared * (3 * radius - height)
			return 1 / 3 * pi * pow(SCREAMING_SNAKE_CASE__  ,     2     ) * (3 * radius - height)



def __lowerCAmelCase       (   SCREAMING_SNAKE_CASE_  ,     SCREAMING_SNAKE_CASE_  ,     SCREAMING_SNAKE_CASE_     ):
			if radius_a < 0 or radius_a < 0 or centers_distance < 0:
						raise ValueError("vol_spheres_intersect() only accepts non-negative values"     )
			if centers_distance == 0:
						return vol_sphere(min(SCREAMING_SNAKE_CASE__  ,     SCREAMING_SNAKE_CASE__     )     )

			lowercase__         = (
			    (radius_a - radius_a + centers_distance)
			    * (radius_a + radius_a - centers_distance)
			    / (2 * centers_distance)
			)
			lowercase__         = (
			    (radius_a - radius_a + centers_distance)
			    * (radius_a + radius_a - centers_distance)
			    / (2 * centers_distance)
			)

			return vol_spherical_cap(SCREAMING_SNAKE_CASE__  ,     SCREAMING_SNAKE_CASE__     ) + vol_spherical_cap(SCREAMING_SNAKE_CASE__  ,     SCREAMING_SNAKE_CASE__     )



def __lowerCAmelCase       (   SCREAMING_SNAKE_CASE_  ,     SCREAMING_SNAKE_CASE_  ,     SCREAMING_SNAKE_CASE_     ):

			if radius_a <= 0 or radius_a <= 0 or centers_distance < 0:
						raise ValueError(
						    "vol_spheres_union() only accepts non-negative values, non-zero radius"     )

			if centers_distance == 0:
						return vol_sphere(max(SCREAMING_SNAKE_CASE__  ,     SCREAMING_SNAKE_CASE__     )     )

			return (
			    vol_sphere(SCREAMING_SNAKE_CASE__     )
			    + vol_sphere(SCREAMING_SNAKE_CASE__     )
			    - vol_spheres_intersect(SCREAMING_SNAKE_CASE__  ,     SCREAMING_SNAKE_CASE__  ,     SCREAMING_SNAKE_CASE__     )
			)



def __lowerCAmelCase       (   SCREAMING_SNAKE_CASE_  ,     SCREAMING_SNAKE_CASE_  ,     SCREAMING_SNAKE_CASE_     ):
			if width < 0 or height < 0 or length < 0:
						raise ValueError("vol_cuboid() only accepts non-negative values"     )
			return float(width * height * length     )



def __lowerCAmelCase       (   SCREAMING_SNAKE_CASE_  ,     SCREAMING_SNAKE_CASE_     ):
			if height < 0 or area_of_base < 0:
						raise ValueError("vol_cone() only accepts non-negative values"     )
			return area_of_base * height / 3.0



def __lowerCAmelCase       (   SCREAMING_SNAKE_CASE_  ,     SCREAMING_SNAKE_CASE_     ):
			if height < 0 or radius < 0:
						raise ValueError("vol_right_circ_cone() only accepts non-negative values"     )
			return pi * pow(SCREAMING_SNAKE_CASE__  ,     2     ) * height / 3.0



def __lowerCAmelCase       (   SCREAMING_SNAKE_CASE_  ,     SCREAMING_SNAKE_CASE_     ):
			if height < 0 or area_of_base < 0:
						raise ValueError("vol_prism() only accepts non-negative values"     )
			return float(area_of_base * height     )



def __lowerCAmelCase       (   SCREAMING_SNAKE_CASE_  ,     SCREAMING_SNAKE_CASE_     ):
			if height < 0 or area_of_base < 0:
						raise ValueError("vol_pyramid() only accepts non-negative values"     )
			return area_of_base * height / 3.0



def __lowerCAmelCase       (   SCREAMING_SNAKE_CASE_     ):
			if radius < 0:
						raise ValueError("vol_sphere() only accepts non-negative values"     )
			# Volume is 4/3 * pi * radius cubed
			return 4 / 3 * pi * pow(SCREAMING_SNAKE_CASE__  ,     3     )



def __lowerCAmelCase       (   SCREAMING_SNAKE_CASE_     ):
			if radius < 0:
						raise ValueError("vol_hemisphere() only accepts non-negative values"     )
			# Volume is radius cubed * pi * 2/3
			return pow(SCREAMING_SNAKE_CASE__  ,     3     ) * pi * 2 / 3



def __lowerCAmelCase       (   SCREAMING_SNAKE_CASE_  ,     SCREAMING_SNAKE_CASE_     ):
			if height < 0 or radius < 0:
						raise ValueError("vol_circular_cylinder() only accepts non-negative values"     )
			# Volume is radius squared * height * pi
			return pow(SCREAMING_SNAKE_CASE__  ,     2     ) * height * pi



def __lowerCAmelCase       (   SCREAMING_SNAKE_CASE_  ,     SCREAMING_SNAKE_CASE_  ,     SCREAMING_SNAKE_CASE_     ):
			# Volume - (outer_radius squared - inner_radius squared) * pi * height
			if inner_radius < 0 or outer_radius < 0 or height < 0:
						raise ValueError(
						    "vol_hollow_circular_cylinder() only accepts non-negative values"     )
			if outer_radius <= inner_radius:
						raise ValueError("outer_radius must be greater than inner_radius"     )
			return pi * (pow(SCREAMING_SNAKE_CASE__  ,     2     ) - pow(SCREAMING_SNAKE_CASE__  ,     2     )) * height



def __lowerCAmelCase       (   SCREAMING_SNAKE_CASE_  ,     SCREAMING_SNAKE_CASE_  ,     SCREAMING_SNAKE_CASE_     ):
			# Volume is 1/3 * pi * height *
			#           (radius_1 squared + radius_2 squared + radius_1 * radius_2)
			if radius_a < 0 or radius_a < 0 or height < 0:
						raise ValueError("vol_conical_frustum() only accepts non-negative values"     )
			return (
			    1
			    / 3
			    * pi
			    * height
			    * (pow(SCREAMING_SNAKE_CASE__  ,     2     ) + pow(SCREAMING_SNAKE_CASE__  ,     2     ) + radius_a * radius_a)
			)



def __lowerCAmelCase       (   SCREAMING_SNAKE_CASE_  ,     SCREAMING_SNAKE_CASE_     ):
			if torus_radius < 0 or tube_radius < 0:
						raise ValueError("vol_torus() only accepts non-negative values"     )
			return 2 * pow(SCREAMING_SNAKE_CASE__  ,     2     ) * torus_radius * pow(SCREAMING_SNAKE_CASE__  ,     2     )



def __lowerCAmelCase       (   ):
			print("Volumes:"     )
			print(f'''Cube: {vol_cube(2     ) = }'''     )  # = 8
			print(f'''Cuboid: {vol_cuboid(2  ,     2  ,     2     ) = }'''     )  # = 8
			print(f'''Cone: {vol_cone(2  ,     2     ) = }'''     )  # ~= 1.33
			print(f'''Right Circular Cone: {vol_right_circ_cone(2  ,     2     ) = }'''     )  # ~= 8.38
			print(f'''Prism: {vol_prism(2  ,     2     ) = }'''     )  # = 4
			print(f'''Pyramid: {vol_pyramid(2  ,     2     ) = }'''     )  # ~= 1.33
			print(f'''Sphere: {vol_sphere(2     ) = }'''     )  # ~= 33.5
			print(f'''Hemisphere: {vol_hemisphere(2     ) = }'''     )  # ~= 16.75
			print(f'''Circular Cylinder: {vol_circular_cylinder(2  ,     2     ) = }'''     )  # ~= 25.1
			print(f'''Torus: {vol_torus(2  ,     2     ) = }'''     )  # ~= 157.9
			print(f'''Conical Frustum: {vol_conical_frustum(2  ,     2  ,     4     ) = }'''     )  # ~= 58.6
			print(f'''Spherical cap: {vol_spherical_cap(1  ,     2     ) = }'''     )  # ~= 5.24
			print(f'''Spheres intersetion: {vol_spheres_intersect(2  ,     2  ,     1     ) = }'''     )  # ~= 21.21
			print(f'''Spheres union: {vol_spheres_union(2  ,     2  ,     1     ) = }'''     )  # ~= 45.81
			print(
			    f'''Hollow Circular Cylinder: {vol_hollow_circular_cylinder(1  ,     2  ,     3     ) = }'''     )  # ~= 28.3


if __name__ == "__main__":
							main()








from __future__ import annotations


class        A_					:




      '''simple docstring'''


      def __init__(				self:       Union[str, Any]						,      a:       int				):
       __lowerCamelCase		:							List[Any]							=						data
       __lowerCamelCase		:							Optional[Any]							=						None



class        A_					:




      '''simple docstring'''


      def __init__(				self:       Dict				):
       __lowerCamelCase		:							Dict							=						None




      def      _snake_case	(				self:       Dict						,      a:       int				):
       __lowerCamelCase		:							List[Any]							=						Node(a				)
       __lowerCamelCase		:							Dict							=						self.head
       __lowerCamelCase		:							Optional[int]							=						new_node
       return self.head.data




      def      _snake_case	(				self:       Optional[Any]				):
       __lowerCamelCase		:							Union[str, Any]							=						self.head
       __lowerCamelCase		:							List[Any]							=						self.head
       if self.head:
        while fast_pointer and fast_pointer.next:
         __lowerCamelCase		:							Any							=						fast_pointer.next.next
         __lowerCamelCase		:							str							=						slow_pointer.next
        return slow_pointer.data
       else:
        print('No element found.'				)
        return None


if __name__ == "__main__":
       lowercase_           =	LinkedList()
       for _ in range(int(input().strip())):
              lowercase_           =	int(input().strip())
              link.push(data)
       print(link.middle_element())

