The Street Lamp Management Office plans to install street lamps on both sides of a 1.2-kilometer-long road (both ends are also installed), and install one lamp every 40 meters. Please help to calculate how many street lamps they should prepare at least?
路灯管理处准备在一条长1.2千米的道路两旁安装路灯(两端也要装)，每隔40米安装一盏．请帮助计算一下，他们至少要准备多少盏路灯？
<gadget id="calculator">1_000 / 40</gadget>
<output>25</output>

<gadget id="calculator">1.2 * 25</gadget>
<output>30</output>

<gadget id="calculator">30 + 1</gadget>
<output>31</output>

<gadget id="calculator">31 * 2</gadget>
<output>62</output>

<result>62</result>