A snail climbs up from the bottom of a ditch 20 cm deep. It takes 2 minutes for every 5 cm to climb, and then stops for 1 minute. How many minutes does it take for the snail to climb from the bottom of the ditch to the edge of the ditch?
一只蜗牛从20厘米深的沟底往上爬，每爬5厘米要用2分钟，然后停1分钟．那么这只蜗牛从沟底爬到沟沿上要用多少分钟．
<gadget id="calculator">20 - 5</gadget>
<output>15</output>

<gadget id="calculator">15 / 5</gadget>
<output>3</output>

<gadget id="calculator">2 + 1</gadget>
<output>3</output>

<gadget id="calculator">3 * 3</gadget>
<output>9</output>

<gadget id="calculator">9 + 2</gadget>
<output>11</output>

<result>11</result>