



def 			_lowerCAmelCase				(       lowercase_		,     lowercase_		,     lowercase_		,     lowercase_						):
						UpperCAmelCase					=			len(_UpperCAmelCase						), len(grid[0]						)
						if (
						    min(_UpperCAmelCase		,     _UpperCAmelCase						) < 0
						    or row == row_length
						    or col == col_length
						    or (row, col) in visit
						    or grid[row][col] == 1
						):
												return 0
						if row == row_length - 1 and col == col_length - 1:
												return 1

						visit.add((row, col)						)

						UpperCAmelCase					=			0
						count += depth_first_search(_UpperCAmelCase		,     row + 1		,     _UpperCAmelCase		,     _UpperCAmelCase						)
						count += depth_first_search(_UpperCAmelCase		,     row - 1		,     _UpperCAmelCase		,     _UpperCAmelCase						)
						count += depth_first_search(_UpperCAmelCase		,     _UpperCAmelCase		,     col + 1		,     _UpperCAmelCase						)
						count += depth_first_search(_UpperCAmelCase		,     _UpperCAmelCase		,     col - 1		,     _UpperCAmelCase						)

						visit.remove((row, col)						)
						return count


if __name__ == "__main__":
				import doctest

				doctest.testmod()










"""simple docstring"""


def 			_lowerCAmelCase				(       lowercase_						):

						if not isinstance(lowercase_		,     lowercase_						):
												UpperCAmelCase					=			F"""Input value of [number={number}] must be an integer"""
												raise TypeError(lowercase_						)

						if number < 1:
												UpperCAmelCase					=			F"""Input value of [number={number}] must be > 0"""
												raise ValueError(lowercase_						)

						UpperCAmelCase					=			1

						for i in range(1		,     lowercase_						):
												current_number *= 4 * i - 2
												current_number //= i + 1

						return current_number


if __name__ == "__main__":
				import doctest

				doctest.testmod()





