There are only 15 seats in a row of chairs, and some of the seats are already occupied. Lele came to see that no matter which seat he sat in, he would always be adjacent to the seated people. Question: How many people are at least seated before Lele?
一排椅子只有15个座位，部分座位已有人就座，乐乐来后一看，他无论坐在哪个座位，都将与已就座的人相邻．问：在乐乐之前已就座的最少有几人？
<gadget id="calculator">15 / 3</gadget>
<output>5</output>

<result>5</result>