Put colorful flags on both sides of the road (both ends), one every 5 meters, a total of 30 flags. How many meters is this road?
在路的两侧插彩旗(两端都插)，每隔5米插一面，一共插了30面．这条路长多少米．
<gadget id="calculator">30 - 1</gadget>
<output>29</output>

<gadget id="calculator">29 * 5</gadget>
<output>145</output>

<result>145</result>