Liu Hua has to do three things: wash clothes for 20 minutes, listen to music for 20 minutes, and do homework for 15 minutes. How many minutes do you think Liu Hua should spend at least?
刘华要做三件事：洗衣服20分钟，听音乐20分钟，写作业15分钟，你觉得刘华最少要用多少分钟．
<gadget id="calculator">20 + 15</gadget>
<output>35</output>

<result>35</result>