A street is AC, turn at B in AC. The length of AB is 240 meters, and the length of BC is 180 meters. Street lamps are installed equidistantly on one side of this street. One street lamp must be installed at points A, B, and C. What is the minimum number of street lamps installed on this street?
一条街道为AC，在AC中的B处转弯．AB长为240米，BC长为180米，在这条街道一侧等距离装路灯，A、B、C三点必须各装一盏路灯，这条街道最少装多少盏路灯．
<gadget id="calculator">240 + 180</gadget>
<output>420</output>

<gadget id="calculator">2 * 2 * 3 * 5</gadget>
<output>60</output>

<gadget id="calculator">420 / 60</gadget>
<output>7</output>

<gadget id="calculator">7 + 1</gadget>
<output>8</output>

<result>8</result>