Once in line, start counting from the left, Xiao Liang reported "8", Xiao Jun reported "10", start counting from the right, Xiao Liang reported "5", how much should Xiao Jun report.
一次排队，从左边开始报数，小亮报了"8"，小军报了"10"，从右边开始报数，小亮报了"5"，小军应报多少．
<gadget id="calculator">5 - 2</gadget>
<output>3</output>

<result>3</result>