Three Class 1 students line up in three rows to do morning exercises, and the number of three rows is equal. Xiaohong is in the middle row. Counting from left to right, she is the sixth; counting from right to left, she is the seventh. How many people are there in the class?
三1班同学排成三排做早操，三排人数相等．小红排在中间一排．从左往右数，她是第6个；从右往左数，她是第7个，全班共有多少个人．
<gadget id="calculator">7 - 1</gadget>
<output>6</output>

<gadget id="calculator">6 + 6</gadget>
<output>12</output>

<gadget id="calculator">12 * 3</gadget>
<output>36</output>

<result>36</result>