






from math import factorial

def   _lowerCamelCase						(    __A     :				int = 20			)   ->       int:
    _UpperCAmelCase					:   Tuple      	=					2 * n  # middle entry of odd rows starting at row 3 is the solution for n = 1,
    # 2, 3,...
    _UpperCAmelCase					:   Optional[int]      	=					n // 2

    return int(factorial(UpperCAmelCase_			) / (factorial(UpperCAmelCase_			) * factorial(n - k			))			)


if __name__ == "__main__":
  import sys

  if len(sys.argv) == 1:
    print(solution(20))
  else:
    try:
      SCREAMING_SNAKE_CASE							=    int(sys.argv[1])
      print(solution(n))
    except ValueError:
      print('Invalid entry - please enter a number.')






from __future__ import annotations
def 							SCREAMING_SNAKE_CASE_	(					UpperCAmelCase_	:     list[int | float]			,							UpperCAmelCase_	:     int			,							UpperCAmelCase_	:     int				)			->						int | float:
       if len(UpperCAmelCase_				) == 0:
              raise ValueError('''find_max() arg is an empty sequence'''				)
       if (
           left >= len(UpperCAmelCase_				)
           or left < -len(UpperCAmelCase_				)
           or right >= len(UpperCAmelCase_				)
           or right < -len(UpperCAmelCase_				)
       ):
              raise IndexError('''list index out of range'''				)
       if left == right:
              return nums[left]
       SCREAMING_SNAKE_CASE_							:				Optional[int]		=(left + right) >> 1  # the middle
       SCREAMING_SNAKE_CASE_							:				Dict		=find_max(UpperCAmelCase_			,							UpperCAmelCase_			,							UpperCAmelCase_				)  # find max in range[left, mid]
       SCREAMING_SNAKE_CASE_							:				Dict		=find_max(UpperCAmelCase_			,							mid + 1			,							UpperCAmelCase_				)  # find max in range[mid + 1, right]

       return left_max if left_max >= right_max else right_max


if __name__ == "__main__":
 import doctest

 doctest.testmod(verbose=True)
