In the sports meeting, colorful flags were placed on one side of the stadium, with one side every 2 meters, and a total of 51 flags were inserted. What is the distance from the first side to the last side in meters?
运动会上，在体育场的一侧插彩旗，每隔2米插一面，一共插了51面，从第一面到最后一面的距离是多少米．
<gadget id="calculator">51 - 1</gadget>
<output>50</output>

<gadget id="calculator">50 * 2</gadget>
<output>100</output>

<result>100</result>