Dragon boat races are held on the Xiujiang River during the Dragon Boat Festival. Colorful flags (both ends) are planted on both sides of a 800-meter-long river, and one is inserted every 2 meters. How many colored flags are used?
端午节在绣江举行龙舟大赛，在一段800米长河面两岸插彩旗(两端都插)，每隔2米插一面，要用多少面彩旗？
<gadget id="calculator">800 / 2</gadget>
<output>400</output>

<gadget id="calculator">400 + 1</gadget>
<output>401</output>

<gadget id="calculator">401 * 2</gadget>
<output>802</output>

<result>802</result>