The students are doing exercises. Xiao Lin is standing in the 7th column from the left and the 14th column from the right. The 11th from the front is the 13th from the back. The number of students in each column is the same. How many students are doing the exercises? ．
同学们做操，小林站在左起第7列，右起第14列，从前面数是第11个，从后面数是第13个，每列人数相同，做操的同学一共有多少人？．
<gadget id="calculator">14 - 1</gadget>
<output>13</output>

<gadget id="calculator">7 + 13</gadget>
<output>20</output>

<gadget id="calculator">13 - 1</gadget>
<output>12</output>

<gadget id="calculator">11 + 12</gadget>
<output>23</output>

<gadget id="calculator">20 * 23</gadget>
<output>460</output>

<result>460</result>