One side of an isosceles triangle is 4 cm long and the other side is 8 cm long. What is the minimum length of rope needed to enclose this isosceles triangle?
一个等腰三角形的一条边长4厘米，另一条边长8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">8 - 4</gadget>
<output>4</output>

<gadget id="calculator">4 + 8 + 5</gadget>
<output>17</output>

<result>17</result>