Put colorful flags on the side of a road, from the beginning to the end, and the distance between every two flags is the same. After the flags are planted, there are 11 intervals. How many flags have been planted.
在一条路边插彩旗，从头到尾插，每两面旗之间的距离一样，插旗后数出有11个间隔．插了多少面彩旗．
<gadget id="calculator">11 + 1</gadget>
<output>12</output>

<result>12</result>