There are three bridges, the first is 287 meters long, the second is 85 meters longer than the first, and the third is 142 meters shorter than the total length of the first and second. How long is the third bridge?
三座桥，第一座长287米，第二座比第一座长85米，第三座比第一座与第二座的总长短142米．第三座桥长多少米？
<gadget id="calculator">287 + 85</gadget>
<output>372</output>

<gadget id="calculator">372 - 142</gadget>
<output>230</output>

<gadget id="calculator">287 + 230</gadget>
<output>517</output>

<result>517</result>