A rectangle is 18 decimeters long and 15 decimeters wide. What is the perimeter of the square if the largest square is to be cut from it?
一个长方形，长是18分米，宽是15分米．如果要从中截取一个最大的正方形，这个正方形的周长是多少？
<gadget id="calculator">15 * 4</gadget>
<output>60</output>

<result>60</result>