Five students named Zhao, Qian, Sun, Li and Zhou are one year older than the other, and they are 50 years old in total. It is known that Zhao is older than Li; Sun is younger than Qian; Qian is older than Li; Zhou is younger than Zhao; then How old is Sun?
赵、钱、孙、李和周姓五个同学，他们一个比一个大一岁，合计50岁，现知赵比李大；孙比钱，比周小；钱比李大；周比赵小；那么孙的年龄是多少岁．
<gadget id="calculator">50 / 5</gadget>
<output>10</output>

<result>10</result>