Microsoft Corporation of the United States has such a recruitment test question: one night, four members of a certain choir must rush to the concert venue in the shortest time, and they must cross a bridge on the way. They only have one flashlight. At most two people can cross the bridge together at a time. When crossing the bridge, you must hold a flashlight, so someone has to bring the flashlight with you. The time for four people to cross the bridge is 1 minute, 2 minutes, 5 minutes, and 10 minutes respectively. At least how many minutes will it take all four of them to cross the river?
美国微软公司有这样一道招聘试题：一天晚上，某合唱团四人必须在最短的时间内赶到演唱会场，途中必须过一座桥，他们只有一只手电筒．每次最多可以由两人同行一起过桥．过桥时，必须手持手电筒，所以就得有人把手电筒带来带去．四人过桥的时间分别是1分钟、2分钟、5分钟、10分钟．至少需要多少分钟四人都过了河？
<gadget id="calculator">2 + 1 + 10 + 2 + 2</gadget>
<output>17</output>

<result>17</result>