There are three small flags in red, yellow, and blue colors, one or two of which are selected to be raised on the flagpole to represent a signal respectively. How many different signals can be represented in total?
有红、黄、蓝三种颜色的小旗各一面，从中选用1面或2面升上旗杆，分别用来表示一种信号．一共可以表示多少种不同的信号？
<gadget id="calculator">3 * 2</gadget>
<output>6</output>

<gadget id="calculator">3 + 6</gadget>
<output>9</output>

<result>9</result>