Xiaodong listens to music for 15 minutes before going to bed at night, boils water for 8 minutes, warms milk for 3 minutes, and drinks milk for 2 minutes. How many minutes does it take him to finish these things?
小东晚上睡觉前要听音乐15分钟，烧水8分钟，热牛奶3分钟，喝牛奶2分钟．他做完这些事情至少要用多少分钟．
<result>15</result>