A triangle is formed by three small sticks, two of which are 5 cm long and 10 cm long, what is the longest perimeter of the triangle in cm? (fill in centimeters)
用三根小棒围成一个三角形，其中两根小棒长分别是5厘米、10厘米，这个三角形的周长最长是多少厘米．(填整厘米数)
<gadget id="calculator">10 - 5</gadget>
<output>5</output>

<gadget id="calculator">10 - 5 - 1</gadget>
<output>4</output>

<gadget id="calculator">5 + 10 + 10 + 4</gadget>
<output>29</output>

<result>29</result>