


'''simple docstring'''

from __future__ import annotations
class   __lowerCAmelCase						:





      '''simple docstring'''






      def __init__(self   :   Dict       ,						UpperCamelCase   :   int			):

             '''simple docstring'''







             lowercase__				      =			data
             lowercase__				      =			None






class   __lowerCAmelCase						:





      '''simple docstring'''






      def __init__(self   :   Dict			):

             '''simple docstring'''







             lowercase__				      =			None



      def 				UpperCamelCase__		(self   :   Union[str, Any]       ,						UpperCamelCase   :   int			):

             '''simple docstring'''







             lowercase__				      =			Node(UpperCamelCase			)
             lowercase__				      =			self.head
             lowercase__				      =			new_node
             return self.head.data






      def 				UpperCamelCase__		(self   :   int			):

             '''simple docstring'''







             lowercase__				      =			self.head
             lowercase__				      =			self.head
             if self.head:
                    while fast_pointer and fast_pointer.next:
                           lowercase__				      =			fast_pointer.next.next
                           lowercase__				      =			slow_pointer.next
                    return slow_pointer.data
             else:
                    print('''No element found.'''			)
                    return None


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








'''simple docstring'''

import math
import os

import cva
import numpy as np

lowerCamelCase							:       Optional[Any]  						=     2_5_5.0

def _SCREAMING_SNAKE_CASE				(A  ,			A	)	->	float:






       """simple docstring"""







       lowercase__				      =			np.mean((original - contrast) ** 2	)
       if mse == 0:
              return 100

       return 20 * math.logaa(PIXEL_MAX / math.sqrt(A	)	)

def _SCREAMING_SNAKE_CASE				()	->	None:






       """simple docstring"""







       lowercase__				      =			os.path.dirname(os.path.realpath(A	)	)
       # Loading images (original image and compressed image)
       lowercase__				      =			cva.imread(os.path.join(A  ,			'''image_data/original_image.png'''	)	)
       lowercase__				      =			cva.imread(os.path.join(A  ,			'''image_data/compressed_image.png'''	)  ,			1	)

       lowercase__				      =			cva.imread(os.path.join(A  ,			'''image_data/PSNR-example-base.png'''	)	)
       lowercase__				      =			cva.imread(
           os.path.join(A  ,			'''image_data/PSNR-example-comp-10.jpg'''	)  ,			1	)

       # Value expected: 29.73dB
       print('''-- First Test --'''	)
       print(f"PSNR value is {peak_signal_to_noise_ratio(A  ,			A	)} dB"	)

       # # Value expected: 31.53dB (Wikipedia Example)
       print('''\n-- Second Test --'''	)
       print(f"PSNR value is {peak_signal_to_noise_ratio(A  ,			A	)} dB"	)


if __name__ == "__main__":
 main()




