The school provides nutritious meals for students, ordered 950 bottles of bright milk, the senior grades took away 328 bottles, the lower grades took away 355 bottles, and the rest were for the middle graders. How many bottles of milk do the middle graders have?
学校为学生开设营养餐，订了950瓶光明牛奶，高年级取走了328瓶，低年级取走了355瓶，剩下的是中年级的，中年级有多少瓶牛奶？
<gadget id="calculator">950 - 328 - 355</gadget>
<output>267</output>

<result>267</result>