A rectangular piece of paper is 18 cm long and 15 cm wide. Cut out the largest square from it. What is the perimeter of the remaining rectangle in cm?
一张长方形的纸，长18厘米，宽15厘米，从中剪下一个最大的正方形，余下的长方形周长是多少厘米？
<gadget id="calculator">18 - 15</gadget>
<output>3</output>

<gadget id="calculator">15 + 3</gadget>
<output>18</output>

<gadget id="calculator">18 * 2</gadget>
<output>36</output>

<result>36</result>