

from __future__ import annotations

import re



def  _A  (			SCREAMING_SNAKE_CASE			):

	def alphanum_key(SCREAMING_SNAKE_CASE			):
		return [int(SCREAMING_SNAKE_CASE			) if s.isdigit() else s.lower() for s in re.split("([0-9]+)"  ,SCREAMING_SNAKE_CASE			)]

	return sorted(SCREAMING_SNAKE_CASE  ,key=SCREAMING_SNAKE_CASE			)


if __name__ == "__main__":
					import doctest

					doctest.testmod()






_lowerCAmelCase     :			Optional[int]    ={
    """+""": lambda x, y: x + y,
    """-""": lambda x, y: x - y,
    """*""": lambda x, y: x * y,
    """/""": lambda x, y: x / y,
}



def  _A  (			SCREAMING_SNAKE_CASE			):
	return c.isdigit()



def  _A  (			SCREAMING_SNAKE_CASE			):
	UpperCAmelCase__:  str		       =   []

	# iterate over the string in reverse order
	for c in expression.split()[::-1]:
		# push operand to stack
		if is_operand(SCREAMING_SNAKE_CASE			):
			stack.append(int(SCREAMING_SNAKE_CASE			)			)

		else:
			# pop values from stack can calculate the result
			# push the result onto the stack again
			UpperCAmelCase__:  Any		       =   stack.pop()
			UpperCAmelCase__:  int		       =   stack.pop()
			stack.append(calc[c](SCREAMING_SNAKE_CASE  ,SCREAMING_SNAKE_CASE			)			)

	return stack.pop()


# Driver code
if __name__ == "__main__":
					_lowerCAmelCase     :			Optional[int]    ="""+ 9 * 2 6"""
					print(evaluate(test_expression))

					_lowerCAmelCase     :			Optional[Any]    ="""/ * 10 2 + 4 1 """
					print(evaluate(test_expression))