There is a row of trees beside the road in the park, and the distance between each tree is 3 meters. What is the distance between the first tree and the sixth tree?
公园的路旁有一排树，每棵树之间相隔3米，第一棵树和第六棵树之间相隔多少米．
<gadget id="calculator">6 - 1</gadget>
<output>5</output>

<gadget id="calculator">3 * 5</gadget>
<output>15</output>

<result>15</result>