The lengths of 4 small rods are 2 cm, 3 cm, 5 cm, and 7 cm. Choose three of them and form a triangle. What is the perimeter of the triangle in cm?
4根小棒长分别是2厘米，3厘米、5厘米，7厘米，选其中的三根，围成一个三角形，三角形的周长是多少厘米．
<gadget id="calculator">3 + 2 + 3 + 7</gadget>
<output>15</output>

<result>15</result>