Class 1 of the second year lined up to do exercises. Xiao Ming was the 6th from the front, the 4th from the back, the 5th from the left, and the 3rd from the right. How many people are there in this class?
二年1班同学排队做操，小明从前数第6个，从后数第4个，从左数第5个，从右数第3个，他们这班一共多少个人．
<gadget id="calculator">3 - 1</gadget>
<output>2</output>

<gadget id="calculator">5 + 2</gadget>
<output>7</output>

<gadget id="calculator">4 - 1</gadget>
<output>3</output>

<gadget id="calculator">6 + 3</gadget>
<output>9</output>

<gadget id="calculator">7 * 9</gadget>
<output>63</output>

<result>63</result>