


def      __lowerCAmelCase    (				snake_case						:     int			)							->				int:
   return n * (2 * n - 1)



def      __lowerCAmelCase    (				snake_case						:     int			)							->				bool:
   __lowerCamelCase:					Optional[int]	 =						(1 + 24 * n) ** 0.5
   return ((1 + root) / 6) % 1 == 0



def      __lowerCAmelCase    (				snake_case						:     int = 144			)							->				int:
   __lowerCamelCase:					Any	 =						start
   __lowerCamelCase:					Optional[Any]	 =						hexagonal_num(snake_case			)
   while not is_pentagonal(snake_case			):
      n += 1
      __lowerCamelCase:					Union[str, Any]	 =						hexagonal_num(snake_case			)
   return num


if __name__ == "__main__":
   print(F"""{solution()} = """)






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



def      __lowerCAmelCase    (				snake_case						:     Union[str, Any]			)							->				str:
   return c.isdigit()



def      __lowerCAmelCase    (				snake_case						:     Optional[Any]			)							->				str:
   __lowerCamelCase:					List[str]	 =						[]

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

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

   return stack.pop()


# Driver code
if __name__ == "__main__":
   _A		:					int          =							'''+ 9 * 2 6'''
   print(evaluate(test_expression))

   _A		:					str          =							'''/ * 10 2 + 4 1 '''
   print(evaluate(test_expression))


