Divide the circle into 4 different sectors. Each sector is dyed with one of the three colors red, white and blue. It is required that adjacent sectors be dyed in different colors. How many dyeing methods are there?
将圆分成4个互不相同的扇形，每个扇形用红、白、蓝三种颜色中一种染色，要求相邻扇形所染的颜色不同，问有多少种染法？
<gadget id="calculator">3 * 2 * 2</gadget>
<output>12</output>

<gadget id="calculator">3 * 2 * 1 * 1</gadget>
<output>6</output>

<gadget id="calculator">12 + 6</gadget>
<output>18</output>

<result>18</result>