

from __future__ import annotations



class   __lowerCamelCase :







       def __init__( self:   Any,A_:   int				):






            '''simple docstring'''




            __UpperCamelCase   = data
            __UpperCamelCase   = None



class   __lowerCamelCase :







       def __init__( self:   Optional[int]				):






            '''simple docstring'''




            __UpperCamelCase   = None







       def 		snake_case_  ( self:   Union[str, Any],A_:   int				):






            '''simple docstring'''




            __UpperCamelCase   = Node(A_				)
            __UpperCamelCase   = self.head
            __UpperCamelCase   = new_node
            return self.head.data







       def 		snake_case_  ( self:   List[str]				):






            '''simple docstring'''




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


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






def 		_A		(		_lowercase   )				->   bool:


     """simple docstring"""


     if not isinstance(_lowercase				,     _lowercase   ):
          raise ValueError('Input series is not valid, valid series - [1, 2/3, 2]'   )
     if len(_lowercase   ) == 0:
          raise ValueError('Input list must be a non empty list'   )
     if len(_lowercase   ) == 1 and series[0] != 0:
          return True
     __UpperCamelCase   = []
     __UpperCamelCase   = len(_lowercase   )
     for i in range(0				,     _lowercase   ):
          if series[i] == 0:
               raise ValueError('Input series cannot have 0 as an element'   )
          rec_series.append(1 / series[i]   )
     __UpperCamelCase   = rec_series[1] - rec_series[0]
     for index in range(2				,     _lowercase   ):
          if rec_series[index] - rec_series[index - 1] != common_diff:
               return False
     return True






def 		_A		(		_lowercase   )				->   float:


     """simple docstring"""


     if not isinstance(_lowercase				,     _lowercase   ):
          raise ValueError('Input series is not valid, valid series - [2, 4, 6]'   )
     if len(_lowercase   ) == 0:
          raise ValueError('Input list must be a non empty list'   )
     __UpperCamelCase   = 0
     for val in series:
          answer += 1 / val
     return len(_lowercase   ) / answer


if __name__ == "__main__":
    import doctest

    doctest.testmod()


