Four people crossed a single-plank bridge at night, and they only had one flashlight. And this single-plank bridge allows at most two people to pass at the same time, and you must hold a flashlight when crossing the bridge, so someone has to bring the flashlight with you. When two people walk together, the slower speed prevails. The time for four people to cross the bridge is 1 minute, 2 minutes, 5 minutes and 10 minutes respectively. How many minutes does it take for the four of them to cross the bridge?
有四个人夜间过一座独木桥，他们只有一只手电筒．而这座独木桥一次最多允许两人同时通过，而过桥的时候必须持有手电筒，所以就得有人把手电筒带来带去．两人同行时以较慢者的速度为准，四人过桥时间分别是1分、2分、5分和10分．他们四人过完桥最少需要多少分钟．
<gadget id="calculator">2 + 1 + 10 + 2 + 2</gadget>
<output>17</output>

<result>17</result>