A 15-meter-long fence surrounds a rectangle against one wall. If the length and width of the rectangle are both integers, what is the maximum area of the rectangle?
用15米长的栅栏靠一面墙围一个长方形，如果长方形的长和宽都是整数，长方形的面积最大是多少？
<gadget id="calculator">7 * 4</gadget>
<output>28</output>

<result>28</result>