On both sides of a 30-meter-long straight road, a colorful flag is inserted every 3 meters. If both ends of each side are inserted, how many flags are needed in total?
一条30米长的直道两边，每隔3米插一面彩旗．如果每边的两端都要插，一共需要多少面彩旗？
<gadget id="calculator">30 / 3</gadget>
<output>10</output>

<gadget id="calculator">10 + 1</gadget>
<output>11</output>

<gadget id="calculator">11 * 2</gadget>
<output>22</output>

<result>22</result>