During the festival, Xiao Ming arranged 6 colored lights in a row, including 2 red lights and 4 green lights. If the two red lights are not adjacent, how many different arrangements are there? (Where "red green red green green green" and "green green green red green red" types are counted as one)
节日期间，小明将6个彩灯排成一列，其中有2个红灯，4个绿灯如果两个红灯不相邻，则不同的排法有多少．(其中"红绿红绿绿绿"与"绿绿绿红绿红"类型的算作一种)
<gadget id="calculator">4 + 2 + 0 + 0</gadget>
<output>6</output>

<result>6</result>