An isosceles triangle has two side lengths of 5 cm and 4 cm respectively. How many centimeters of rope is required to enclose this isosceles triangle?
一个等腰三角形，有两条边长分别为5厘米、4厘米，围成这个等腰三角形至少需要多少厘米长的绳子．
<gadget id="calculator">4 * 2</gadget>
<output>8</output>

<gadget id="calculator">8 + 5</gadget>
<output>13</output>

<result>13</result>