A rectangular photo frame is 30 cm long and 15 cm wide. If you put lace around it, what is the minimum length of the lace?
一个长方形相框长30厘米，宽15厘米，如果给它四周贴上花边，花边至少长多少厘米．
<gadget id="calculator">30 + 15</gadget>
<output>45</output>

<gadget id="calculator">45 * 2</gadget>
<output>90</output>

<result>90</result>