The school has three extracurricular activity groups: reading aloud, music, and calligraphy. It is stipulated that each student participates in two interest groups, and the minimum number of students can ensure that at least 6 students participate in the interest groups.
学校有朗读、音乐、书法三个课外活动小组，规定每个学生参加两个兴趣小组，至少有多少名学生，才能保证至少有6名学生参加兴趣小组的情况完全相同．
<gadget id="calculator">6 - 1</gadget>
<output>5</output>

<gadget id="calculator">3 * 5</gadget>
<output>15</output>

<gadget id="calculator">15 + 1</gadget>
<output>16</output>

<result>16</result>