The students line up to do exercises, and there are the same number of people in each row. Xiaohong's position is the third from the left, and the third from the right; the third from the front, and the third from the back ． How many students do exercises?
同学们排队做操，每行人数同样多，小红的位置从左数起是第3个，从右数起是第3个；从前数起是第3个，从后数起也是第3个．做操的同学共有多少个．
<gadget id="calculator">3 - 1</gadget>
<output>2</output>

<gadget id="calculator">3 + 2</gadget>
<output>5</output>

<gadget id="calculator">5 * 5</gadget>
<output>25</output>

<result>25</result>